The international best-seller that makes mathematics a thrilling exploration In twelve dreams, Robert, a boy who hates math, meets a Number Devil, who leads him to discover the amazing world of numbers: infinite numbers, prime numbers, Fibonacci numbers, numbers that magically appear in triangles, and numbers that expand without end. As we dream with him, we are taken furth The international best-seller that makes mathematics a thrilling exploration In twelve dreams, Robert, a boy who hates math, meets a Number Devil, who leads him to discover the amazing world of numbers: infinite numbers, prime numbers, Fibonacci numbers, numbers that magically appear in triangles, and numbers that expand without end. As we dream with him, we are taken further and further into mathematical theory, where ideas eventually take flight, until everyone--from those who fumble over fractions to those who solve complex equations in their heads--winds up marveling at what numbers can do. Hans Magnus Enzensberger is a true polymath, the kind of superb intellectual who loves thinking and marshals all of his charm and wit to share his passions with the world. In The Number Devil, he brings together the surreal logic of Alice in Wonderland and the existential geometry of Flatland with the kind of math everyone would love, if only they had a number devil to teach them.

# The Number Devil: A Mathematical Adventure

The international best-seller that makes mathematics a thrilling exploration In twelve dreams, Robert, a boy who hates math, meets a Number Devil, who leads him to discover the amazing world of numbers: infinite numbers, prime numbers, Fibonacci numbers, numbers that magically appear in triangles, and numbers that expand without end. As we dream with him, we are taken furth The international best-seller that makes mathematics a thrilling exploration In twelve dreams, Robert, a boy who hates math, meets a Number Devil, who leads him to discover the amazing world of numbers: infinite numbers, prime numbers, Fibonacci numbers, numbers that magically appear in triangles, and numbers that expand without end. As we dream with him, we are taken further and further into mathematical theory, where ideas eventually take flight, until everyone--from those who fumble over fractions to those who solve complex equations in their heads--winds up marveling at what numbers can do. Hans Magnus Enzensberger is a true polymath, the kind of superb intellectual who loves thinking and marshals all of his charm and wit to share his passions with the world. In The Number Devil, he brings together the surreal logic of Alice in Wonderland and the existential geometry of Flatland with the kind of math everyone would love, if only they had a number devil to teach them.

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4out of 5Elaine–I love the idea of a novel that relies on and promotes interest in math, but the execution here just fell way short for me. The story itself - that a boy who hates math learns to like it through a series of dreams in which he interacts with a Number Devil - is a little thin and repetitive. But what I found bothered me the most were the explanations of the math concepts. I've seen some great nonfiction books that make math concepts interesting AND explain them in multiple ways for students who ca I love the idea of a novel that relies on and promotes interest in math, but the execution here just fell way short for me. The story itself - that a boy who hates math learns to like it through a series of dreams in which he interacts with a Number Devil - is a little thin and repetitive. But what I found bothered me the most were the explanations of the math concepts. I've seen some great nonfiction books that make math concepts interesting AND explain them in multiple ways for students who catch on differently. This book would introduce a concept, state some random things you could do with it (but usually not why you might want to), and move on without trying to address WHY something was the way it was, or multiple learning styles. Another thing I couldn't totally get on board with was renaming math concepts. I get that some of the terms might have been easier to remember, but the real name for them is never mentioned, so kids might come away knowing all about "prima donna numbers" and never put together that they're really called prime numbers. And some seemed unnecessary - is "Bonacci numbers" really that much easier to remember than "Fibonacci numbers"? I just had such high hopes for this one and came away disappointed.

5out of 5Lance Greenfield–This book makes maths fun, even for those little people who believe it to be a laborious trudge through treacle. In fact, that would describe Robert, the main character in this book. He has been struggling with maths for as long as he can remember. One night, he dreams that he meets a little devil, The Number Devil, who teaches him, as he sleeps, all sorts of useful tricks with numbers. When you enjoy something, and gain immediate benefit, you obviously learn more. My Dad made all aspects of mathe This book makes maths fun, even for those little people who believe it to be a laborious trudge through treacle. In fact, that would describe Robert, the main character in this book. He has been struggling with maths for as long as he can remember. One night, he dreams that he meets a little devil, The Number Devil, who teaches him, as he sleeps, all sorts of useful tricks with numbers. When you enjoy something, and gain immediate benefit, you obviously learn more. My Dad made all aspects of mathematics enjoyable for me from a very early age, almost from when I could walk and talk, by relating what we were seeing in the real world to mathematics in some way. He didn't label the principles as geometry, algebra, arithmetic, and so on. He just mde it all part of my world. Consquently, I never scored less than 90% in any maths test or exam in my life. I just enjoy maths as much as living. The same holds for Robert, and for readers of this lovely little book. My grandson was hating maths, and couldn't see the point. When I took him through the first chapter of The Number Devil, he could suddenly, and effortlessly, multiply 11 by 11, 1111 by 1111, 1111111 by 1111111 and so on. He also learned, through self motivation inspired by his "new trick" to multiply any number you could throw at him by eleven. This may seem a small step, but you can believe me when I tell you that it was a massive step for Alfie. Furthermore, he couldn't wait to get to school the next day to show his new skills to his class-mates and his teacher. That wasn't all. There was much more magic to be revealed in this great little book, and I would encourage anyone to share it with their children, even if they are already very numerate. It just gives them, and you, a new spin on an ancient subject.

5out of 5David Madrigal–This book was by far the most interesting book I have read in years. I found it really interesting as the concepts in mathematics were very interesting, yet explained in simple terms. (view spoiler)[ The Number Devil is about a boy named Robert, who finds himself dreaming about himself and the Number Devil, who has a vast knowledge on mathematics. Each night for thirteen nights, the Number Devil teaches Robert about numbers and their properties. During the earlier nights, Robert doesn’t apprecia This book was by far the most interesting book I have read in years. I found it really interesting as the concepts in mathematics were very interesting, yet explained in simple terms. (view spoiler)[ The Number Devil is about a boy named Robert, who finds himself dreaming about himself and the Number Devil, who has a vast knowledge on mathematics. Each night for thirteen nights, the Number Devil teaches Robert about numbers and their properties. During the earlier nights, Robert doesn’t appreciate the Number Devil interfering in his dreams, but in the later nights, Robert looks forward to the Number Devil visiting him and teaching him all about the purpose of numbers. There are many properties explored throughout the book, like triangle numbers and Bonacci numbers, and the book teaches you about concepts these numbers can be applied to in real world situations, like the birth of rabbits, or the arrangement of desks. Towards the end, Robert finds that numbers aren’t what they seem, and that the way you organize them matters. When the Number Devil says goodbye, Robert feels more prepared for his math class, as in the beginning of the thirteen nights he hated it and had no interest in it. Thanks to the Number Devil, he knows more and his life in mathematics is easier. (hide spoiler)] This book teaches you about mathematics in general, like the fact that some properties of numbers can help you in solving problems. I rated this book five stars because of the complexity in such a simple bedtime story. I would recommend this book to anyone who likes math, but I’d also reccomend this book to someone who doesn’t like math as well, as this book teaches you about math without you having to struggle. The Number Devil is one of the best books I have ever read, the story is easy to follow and it really makes you think. I enjoyed this book myself because I love learning new concepts as well as how they make sense in the real world.

4out of 5Tung–Imagine that a math teacher wanted to write a children's book to show kids how cool math really was; but since it's a math teacher and not an English teacher doing the writing, all you end up with are math concepts written out in analogies similar to what you'd hear in a math classroom -- that's what this book is like. The story is about a boy named Robert who hates his math class and math teacher and by extension math in general. He falls asleep and over a series of twelve different dreams over Imagine that a math teacher wanted to write a children's book to show kids how cool math really was; but since it's a math teacher and not an English teacher doing the writing, all you end up with are math concepts written out in analogies similar to what you'd hear in a math classroom -- that's what this book is like. The story is about a boy named Robert who hates his math class and math teacher and by extension math in general. He falls asleep and over a series of twelve different dreams over twelve different nights, he learns about different math concepts from a dream guide who calls himself a Number Devil. The devil presents math concepts in kid-friendly terms and even uses kid-friendly language to describe them. For example, instead of using the term exponents, the devil uses the term "hopping"; he also calls prime numbers prima donna numbers. And obvious spoiler, but Robert comes to appreciate math by the end of the book. My first criticism is that half of the number concepts aren't described as cleverly as prima donna numbers. Calling Fibonacci numbers Bonacci numbers or Pascal's Triangle a Numbers Triangle is simply lazy. My second and bigger criticism is that the prose is terrible. The dialogue between Robert and the devil reads far less like a boy talking to a dream figure, and more like a math teacher talking to an imaginary student who is engaged in his lesson. I like math and find it fascinating, but this book irritated me more than made me appreciate numbers. I'm sure math teachers are massive fans of this book; I was not.

4out of 5Kelly H. (Maybedog)–Random math thinly disguised as a novel. I get what it's trying to do but it feels more like the kind of characters that kids' textbooks have to make the info more "fun." there isn't a plot here. But if it gets kid's reading about math then go go go. Plus, the illustrations are really cute. Random math thinly disguised as a novel. I get what it's trying to do but it feels more like the kind of characters that kids' textbooks have to make the info more "fun." there isn't a plot here. But if it gets kid's reading about math then go go go. Plus, the illustrations are really cute.

4out of 5Bradman–Great book. It talks about maths in a way that is as simple as 1+1=2. I was way behind in maths going into high school, and I have learnt so much from this book in 1-2 months. I learnt stuff like Fractions, Bonacci/Fibonacci numbers, Decimals, Factorial (Vroom!), Hopping numbers, Prima Donnas, and Triangle numbers. My favorite was the "Hopping Numbers". I spent a good part of a day just writing them all down. I wrote down 55 hopping numbers, and the biggest one I did was 18,014,398,509,481,984, whic Great book. It talks about maths in a way that is as simple as 1+1=2. I was way behind in maths going into high school, and I have learnt so much from this book in 1-2 months. I learnt stuff like Fractions, Bonacci/Fibonacci numbers, Decimals, Factorial (Vroom!), Hopping numbers, Prima Donnas, and Triangle numbers. My favorite was the "Hopping Numbers". I spent a good part of a day just writing them all down. I wrote down 55 hopping numbers, and the biggest one I did was 18,014,398,509,481,984, which was too big for my calculator to check. "All Englishmen are liars," the man mumbled, "but if I say it, what then? I'm an Englishman myself. so I'm lying too. But then what I've just said - namely, that all Englishmen are liars - is not true. but if Englishmen tell the truth, then what I said before must be true as well. In other words, we are liars." A must read book. :D First 55 Hopping numbers: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 13427728, 268435456, 67108864, 13427728, 268435456, 536870912, 1073741824, 4294967296, 8589934592, 17179869184, 34359738368, 68719476736, 137438953472, 274877906944, 549755813888, 1099511627776, 2199023255552, 439846511104, 8796093022208, 17592186044416, 35184372088832, 70368744177664, 562949953421312, 1125899906842624, 2251799813685248, 4503599627370496, 9007199254740992, 18014398509481984.

5out of 5Selene–January 8, 2019 - 4 Stars I read this with my grade six students. They figured out the problems as we went. The story/plot itself was kind of boring but I enjoyed the problems and the student solving them.

5out of 5Anne Hamilton–...But as he stood in front of his mirror in his pajamas, brushing his teeth, he felt something tickling his chest and looked down to see a tiny five-pointed star on a thin golden chain. He couldn't believe his eyes. This time his dream had come true! ...After he'd dressed, he took the chain off and stuck it in his pocket: he didn't want his mother asking silly questions. ...Where'd that star come from? she'd want to know the minute she saw it. Boys don't wear jewelry! ...How could he tell he ...But as he stood in front of his mirror in his pajamas, brushing his teeth, he felt something tickling his chest and looked down to see a tiny five-pointed star on a thin golden chain. He couldn't believe his eyes. This time his dream had come true! ...After he'd dressed, he took the chain off and stuck it in his pocket: he didn't want his mother asking silly questions. ...Where'd that star come from? she'd want to know the minute she saw it. Boys don't wear jewelry! ...How could he tell her it was the emblem of a secret order? Perhaps a mathematical fairytale (yes! what a truly delectable combo) is a dubious inclusion in a round-up of the golden ratio in literature. Does a story in which the purpose is clearly didactic and in which the emphasis is on the exposition of the nifty niceties of various numerical patterns really qualify as literature? Isn't a mathematics text thinly disguised as a children's story a bit suspect? In its defence, I have to say that The Number Devil does have the three essential C's of a story - character, conflict and context - so I'm giving it the benefit of the doubt. The plot, moreover, floats as lightly as a feather on a froth of allusions to some truly great tales told by (or about) mathematicians down the ages: the mushrooms of Alice in Wonderland* make an appearance, the cave of Plato** is the setting for one of Robert's dreams, the anecdote about the schoolmaster and young Karl Gauss***is re-enacted by Robert and Mr. Boekel, and the great mathematical mystery which plagued medieval theologians - 'How many angels can dance on the point of a pin?' - is restated in a new guise. Ahhh, what a glorious book! But I didn't give it five stars just because I love mathematics and fairytales. I did it because it made a point I've never ever seen elsewhere. Robert, the young dreamer of The Number Devil, has a problem with mathematics. He hates it. His teacher, the pretzel-loving Mr. Boekel, is apt to ask such sinister questions as: 'If 2 pretzel makers can make 444 pretzels in 6 hours, how long does it take 5 pretzel makers to make 88 pretzels?' Fortunately for Robert and his mathematical future, his dreams are invaded by a chirpy little chap who introduces himself as 'the number devil'. Starting with the number one and its properties, the number devil explores different facets of the realm of mathematics. Robert, despite his initial antagonism, becomes increasingly intrigued. The sixth night of dreaming is devoted to Mr. Bonacci and his rabbit clock (a peculiar eared device where the markings correspond to months rather than hours), while the tenth night of dreaming is devoted to the golden ratio. On that night, the number devil re-introduces the Fibonacci numbers of the sixth night, much to Robert's disgust ('You and your Bonacci!' he exclaims. 'Tell me, is that guy your best friend or something?') and shows him how the golden ratio is hidden in the sequence. Enzensberger has made an interesting observation at this point - and this is what made me decide to include The Number Devil in my catalogue of the golden ratio in literature and to give it five stars. I don't know of anyone else who has actually bothered to point out that it's not just the Fibonacci sequence which turns up the golden ratio. Pick any two numbers (Robert chooses 11 and 17) and use them as the basis of a Fibonacci-like additive sequence: add them together, then add the last number to the total to make a new term and keep on doing this for as long as you please. Pretty soon, the ratio of those last two numbers is going to tend towards the golden ratio, no matter what initial numbers you chose. 'Is it buried in all numbers?' Robert asks. 'It is,' said the number devil. At the end of the book, Robert is awarded the Order of Pythagoras (Fifth Class) - and is given a gold star on a chain. As ever in The Number Devil, no reference is made to the historical precedent, no explanation is given about the allusion. The five-pointed gold star is, however, the symbol of the Pythagorean Brotherhood and Robert is right in thinking of it as the emblem of a secret order. It was exactly that: the pentagram was called 'the number of man' and was the device by which members recognised each other. The Number Devil is a delightful book, where even the most whimsical incidents are drawn from the history of mathematics. I caught quite a few of the allusions, but I suspect just as many went over my head. While there's an extra dimension of pleasure in recognising those hidden references, the book is truly enjoyable anyway. I hope it becomes a modern classic. It certainly deserves just such an accolade. * Alice in Wonderland was written by the mathematician and theologian, Rev. Charles Lutwidge Dodgson under the pseudonym, Lewis Carroll. The famous answer - 'forty-two' - to the question in The Hitchhiker's Guide to the Galaxy 'What is the answer to life, the universe and everything?' is taken from Alice Through the Looking Glass. ** Pythagoras was admired by Plato who used some of his ideas (particularly in what is called the geometry of the 'Platonic solids'). *** The incident at the very end of The Number Devil is similar to a story told of Karl Gauss. The boy, later to become 'The Prince of Mathematicians', was in a class asked by the teacher to add up all the numbers from 1 to 100. Almost at once, Gauss had the correct answer (not a calculator in sight either!). He used the same technique Robert uses to work out the answer.

5out of 5Beth–What do you get when you cross Alice in Wonderland with a small, red, horned man obsessed with numbers? No, it isn't an arithmetic problem - it's a middle school math primer! Robert, a boy who hates math and is frustrated because his teacher doesn't allow calculators, has strange dreams all the time. One night he dreams up a character called the Number Devil, who takes him away to a surreal world of numbers where Robert learns basic math concepts and a few handy shortcuts. After all, says the Num What do you get when you cross Alice in Wonderland with a small, red, horned man obsessed with numbers? No, it isn't an arithmetic problem - it's a middle school math primer! Robert, a boy who hates math and is frustrated because his teacher doesn't allow calculators, has strange dreams all the time. One night he dreams up a character called the Number Devil, who takes him away to a surreal world of numbers where Robert learns basic math concepts and a few handy shortcuts. After all, says the Number Devil, "you learn best when you sleep." Over the course of 12 different evenings, Robert learns factorials, how to find a square root, and more. Concepts such as the importance of the number zero and the idea of infinity are stressed over and over. Robert discovers triangle number, Bonacci numbers, imaginary numbers, and irrational numbers. Did you know that you can take any even number larger than two and find 2 prime number that add up to it? Robert is even able to apply what he's learned in an actual math class. The Number Devil makes up fun - and punny - terms for things. Roots become "rutabagas" (a root vegetable) and prime numbers are "prima donnas." Squaring becomes "number hopping," and factorials (!) are renamed "vrooms." A warning at the end reminds kids to use the proper terms in class. The index doubles as a brief glossary, defining terms in a few words. It is truly remarkable how clearly the theories are presented. Enzensberger translates math to German, and Berner translates the German to English. The concepts are well explained and provide jumping off points for many discussions, from pyramids to mosaics to biographies of mathematicians. Whimsical illustrations and colorful charts and diagrams add to the text. Practical applications relate to nature in many cases. Bonacci numbers are illustrated with rapidly multiplying bunny rabbits. Similar examples would have been great! Related activities include playing with number triangles and making 3-D geometric shapes. There are no pages of practice problems or exercises, although one or two chapters end with a question for a student to solve by extrapolating new information. Middle school teachers can spice up their lectures with a chapter from this book. Homeschoolers can it as a unique supplemental text. While some might object to the negative imagery surrounding math (Robert is in number hell, and learns from a devil), the book may reach some kids relate to the main character. This math-phobic librarian (the only numbers I'm good at are Dewey Decimal ones). Can't wait for the sequel!

5out of 5Jose Moa–This book told as a 12 nights dream of a child with a mathematical devil is a serious attempt to prove that mathematics can be entertaining,interesting,beautiful and fun and not a boring,useless,ugly and hermetic subject. It is aimed mainly to young teens,but is also enjoyable by adults that for some reason hate the maths or have a wrong concept of this field. Is a tale where departing of elemental concepts as natural numbers,prime numbers,powers and square roots introduce more advanced concepts a This book told as a 12 nights dream of a child with a mathematical devil is a serious attempt to prove that mathematics can be entertaining,interesting,beautiful and fun and not a boring,useless,ugly and hermetic subject. It is aimed mainly to young teens,but is also enjoyable by adults that for some reason hate the maths or have a wrong concept of this field. Is a tale where departing of elemental concepts as natural numbers,prime numbers,powers and square roots introduce more advanced concepts as triangular numbers,Pascal triangle and his properties,permutations,combinations,properties of numerable sets of numbers,convergence of power series,divergence of armonic series and a introduction to topological results as the Euler characteristic of a graph and a poliedre and the Klein bottle ending with reflections of the idea of mathematical demostration and a brief decription of the greatest mathematicians. It has no demostrations ,only expositions of concepts and results. All are explained with a simple language and clear and beautiful drawings

4out of 5Kelly Jahng–This book was a lot of fun. I'm a big fan of Flatland, so I enjoy anytime math can be turned into a story. This book doesn't have a ton of story, but just enough to make it a page turner. Robert's math teacher, Mr. Bockel doesn't seem to be a very inspiring educator, doing little else but assigning word problems while surreptitiously munching on pretzels. Robert thinks math is confusing and boring. All that changes when his dreams are visited by a strange genie-like character called The Number D This book was a lot of fun. I'm a big fan of Flatland, so I enjoy anytime math can be turned into a story. This book doesn't have a ton of story, but just enough to make it a page turner. Robert's math teacher, Mr. Bockel doesn't seem to be a very inspiring educator, doing little else but assigning word problems while surreptitiously munching on pretzels. Robert thinks math is confusing and boring. All that changes when his dreams are visited by a strange genie-like character called The Number Devil. Through the course of many visits to The Number Devil's mathematical dreamscape, Robert learns that not only does math make a lot of sense, but it's actually pretty interesting. The Number Devil gives mathematical concepts silly names, calling prime numbers "prima donna numbers" and exponents "hopping numbers," which could be confusing, but there's a guide at the end of the book which explains what everything is really called. I actually think not using the "correct" names might make the book more accessible to kids. Robert has the chance to meet other "number devils," mathematicians from throughout history, and asks why more of them aren't women. It's a great questions, and though the book doesn't delve into that issue too deeply, it's nice to see it addressed.

5out of 5Dany Hdz–Well, that was interestingly cute... like if you took math class in Wonderland or if you studied math on drugs, or something, but I cannot deny it was great. Honestly, I don’t think this book will make you better at math, however it may help you understand some complex theoretical concepts, since it doesn’t focus in the applied mathematics, but rather in the pure theory behind them. The narration is fantastic and creative, and in fact, pretty attractive. Besides, the pictures and dares really co Well, that was interestingly cute... like if you took math class in Wonderland or if you studied math on drugs, or something, but I cannot deny it was great. Honestly, I don’t think this book will make you better at math, however it may help you understand some complex theoretical concepts, since it doesn’t focus in the applied mathematics, but rather in the pure theory behind them. The narration is fantastic and creative, and in fact, pretty attractive. Besides, the pictures and dares really complement the story. So whether you struggle with math or not, I would recommend to read this book. :) P.S. I believe that the fact that the math geniuses are portrayed as devils is a pretty straight forward message... I mean, there’s math hell!! I know maths are mischievous and devilish, but this is literally saying *maths are hell*, isn’t it? Nah, just kidding, haha.

4out of 5May–I've been meaning to read this book for a long time, as it came highly recommended by both my kids. After reading it, I can see why. The author has written a loose structure of a novel in order to painlessly and seamlessly teach children some basic math concepts. Along the way, he makes math fun and interesting and accessible. (I actually happen to think math *is* fun and interesting and accessible, but I realize that not everyone does.) The book is geared towards middle schoolers, but it works w I've been meaning to read this book for a long time, as it came highly recommended by both my kids. After reading it, I can see why. The author has written a loose structure of a novel in order to painlessly and seamlessly teach children some basic math concepts. Along the way, he makes math fun and interesting and accessible. (I actually happen to think math *is* fun and interesting and accessible, but I realize that not everyone does.) The book is geared towards middle schoolers, but it works well for older children and adults as well. It also works well for both people who love math and its intricacies as well as people who are math-phobic, as it provides explanations and projects for experiential learners, all in a fun and light-hearted way. I would best characterize the book as a novel about math. If that intrigues you, then read the book!

4out of 5Anna–I am at my mothers house right now, which for me means rereading childhood classics that did not follow me to uni. This one isn't something I remember reading a lot, but somehow it made it on my nightstand. It's cute, a math book for a young audience, and the beginning works well for me. However, it does become a bit tedious, especially since things are shown, not really explained and weird words are invented to do so. I now know why this didn't become a favorite of mine: you never quite learn wh I am at my mothers house right now, which for me means rereading childhood classics that did not follow me to uni. This one isn't something I remember reading a lot, but somehow it made it on my nightstand. It's cute, a math book for a young audience, and the beginning works well for me. However, it does become a bit tedious, especially since things are shown, not really explained and weird words are invented to do so. I now know why this didn't become a favorite of mine: you never quite learn why things are as they are or why you should care about them in the first place. So either you just like math or you don't - this will not change any attitudes. Still, it has it's moments, and the illustrations are pretty nice.

4out of 5Greenglasses–Funny book about a number devil who meets a boy and converts him from a maths hater to a mathematician. My only bad thing is that it is maths but the story is funny.

5out of 5Jason–This book is a thinly veiled novelization of a few math problems. It's wrapped in a story about a boy with crazy dreams that begins dreaming about math and learning things from a number devil. My impression was that the book got the formula all wrong. The story is nonsensical and tedious, so you're ready to get to the math. The math is then explained via conversation between the main character and the number devil, so you really have to reflect on the topics after each chapter to understand them. This book is a thinly veiled novelization of a few math problems. It's wrapped in a story about a boy with crazy dreams that begins dreaming about math and learning things from a number devil. My impression was that the book got the formula all wrong. The story is nonsensical and tedious, so you're ready to get to the math. The math is then explained via conversation between the main character and the number devil, so you really have to reflect on the topics after each chapter to understand them. You could easily read through the book and learn nothing but the overall story. The worst offense of this book is the made up names for mathematical terms. They have a warning at the end of the book telling readers that they should listen to their teacher and use the proper name instead of the dream term. If you want me to use the correct term, don't teach me the wrong term! For example, they refer to prime numbers as prima donnas, the Fibonacci sequence as Bonacci numbers, and 4! (four factorial) as four vroom! As somebody that already knows the mathematical concepts, this book was a big disappointment. Unless it really grabs a kid's attention, I don't see how this book would be a preferred way of teaching math concepts - it takes longer than an explanation and example of the topic, the explanation gets muddled down, and it teaches the wrong terms.

5out of 5Jane–Nein, Nyet, Non, Nee, Votch, Nej, Nan, Oxi, Minime - how many ways can I say No to this book? As a certified math-phobic, I have to check in once in a while to see just what it is that causes my throat to close, my mind to go blank, and my skin to break out in a rash when faced with anything math related. I thought, "OK, how bad can a kid's book be?" The answer: Pretty fecking awful. Rutabaga numbers? What the hell are they talking about? Bonacci numbers? I thought the man's name was Fibonacci. Nein, Nyet, Non, Nee, Votch, Nej, Nan, Oxi, Minime - how many ways can I say No to this book? As a certified math-phobic, I have to check in once in a while to see just what it is that causes my throat to close, my mind to go blank, and my skin to break out in a rash when faced with anything math related. I thought, "OK, how bad can a kid's book be?" The answer: Pretty fecking awful. Rutabaga numbers? What the hell are they talking about? Bonacci numbers? I thought the man's name was Fibonacci. Excuse me, I need to go take my allergy pills now and go lie down with a soothing book on something I can understand.

4out of 5Sibil–3.5 stars If I was a child I would have loved this book, and I don't love maths. It was an intersting reading and I enjoeyed the things that you can learn while reading it. I think I'll recommend it to every kid (and not) who wants to read about math! 3.5 stars If I was a child I would have loved this book, and I don't love maths. It was an intersting reading and I enjoeyed the things that you can learn while reading it. I think I'll recommend it to every kid (and not) who wants to read about math!

5out of 5Jonathan Donihue–What a truly novel idea for a novel. Absolutely extraordinary! Although this is a book written for a young audience, I, as a 49 year old college student, found it both entertaining and instructional. In addition to a great story, The Number Devil sports some wonderful illustrations and several imaginative crafts projects for the budding mathematician. Whether you have a schoolchild or not, I would encourage you to pick up a copy of The Number Devil. You won't be sorry you did. 😈 😈 😈 What a truly novel idea for a novel. Absolutely extraordinary! Although this is a book written for a young audience, I, as a 49 year old college student, found it both entertaining and instructional. In addition to a great story, The Number Devil sports some wonderful illustrations and several imaginative crafts projects for the budding mathematician. Whether you have a schoolchild or not, I would encourage you to pick up a copy of The Number Devil. You won't be sorry you did. 😈 😈 😈

4out of 5Cali–This book made cry.....and not because it was heart wrenching. This book should go back to the hellhole where it came from. AVOID THIS BOOK AT ALL COSTS. When I bought this books, my family stopped loving me, my girlfriend turned gay, my fish died, and when I opened the yogurt lid, I threw away the yogurt instead of the lid because I was drunk on hatred for this book.

5out of 5Sophia–Interesting information, but I was annoyed by the wrong names for mathematical things. The author explained his reason for this at the end, but I think he could have kept closer to he facts. The book is meant to make non-maths lovers like maths. I think it tries but is still too complex in many parts to do this. I did find some interesting bits.

4out of 5Shiraz–this is honestly just one of those perfect books—i love the writing as well as the illustrations. i also love math but even if you hate math this book will make you think about it a little differently

5out of 5Shannon Rantala–It was a really interesting book. I think students would enjoy reading it since it makes learning math sound fun and exciting.

5out of 5Olive–Wow. This book is like a maths textbook but make it a fictional story. Such a fun read believe it or not. Extremely interesting.

5out of 5Kelly–Amazing book. It teaches advanced mathematics in a way so children can understand. The pictures are really cute, too.

5out of 5Jill–Clearly a math book. I found myself skimming the math and hoping for a story. The math explanations were good and clear, I just got bored and distracted. Maybe better read alod with someone to work the math with.

5out of 5Connie–This is a weird little book. It was originally written in German, and I’m wondering if we’re missing a lot in translation. The dialogue is very stilted. It’s lacking the charm one would expect in a book of this type. This book is about a boy named Robert who hates math. He has dreams where he meets with a devil who calls himself a number devil. He teaches Robert about some of the more crazy and interesting things numbers do. The proper names for these math concepts are not used in the course of t This is a weird little book. It was originally written in German, and I’m wondering if we’re missing a lot in translation. The dialogue is very stilted. It’s lacking the charm one would expect in a book of this type. This book is about a boy named Robert who hates math. He has dreams where he meets with a devil who calls himself a number devil. He teaches Robert about some of the more crazy and interesting things numbers do. The proper names for these math concepts are not used in the course of the book, but an index is provided at the end connecting the proper name with the weird names the number devil calls them. I feel like this is a book that would be best used with a teacher or parent. You have to have a certain understanding of these concepts to get what is being taught. A teacher or parent could use this book with children to discuss and learn about these concepts. If a child is trying to read this on their own, though, I don’t think they will be able to get much out of it. At best it might increase their interest.

5out of 5Passang–This summer I decided to read the book The Number Devil: A Mathematical Adventure by Hans Magnus Enzensberger. The story is about a boy named Robert who hates math because he finds it very boring at school. He keeps dreaming about being eaten by a giant fish or sliding down a never ending slide until one night he suddenly finds himself dreaming about meeting the Number Devil (Teplotaxl). During the twelve nights Robert finds himself learning different mathematical principles every night. In the This summer I decided to read the book The Number Devil: A Mathematical Adventure by Hans Magnus Enzensberger. The story is about a boy named Robert who hates math because he finds it very boring at school. He keeps dreaming about being eaten by a giant fish or sliding down a never ending slide until one night he suddenly finds himself dreaming about meeting the Number Devil (Teplotaxl). During the twelve nights Robert finds himself learning different mathematical principles every night. In the first four nights, Robert learns about the importance of one and zero, exponents, negative numbers, prime numbers, and square roots. After the fourth night, Robert was not able to find the Number Devil until he dreamt of himself on a beach where the Number Devil taught him about triangular numbers. After the sixth dream, Robert’s mother begins to notice the change in his mathematical interest. On the seventh and eighth night Robert learns about Pascal’s triangle and Permutations and Combinations. On the ninth night Robert dreamt he was sick with the flu. The Number Devil appeared beside him and taught him about natural numbers and the characteristics of infinite. On the tenth and eleventh night he learns about irrational numbers and mathematical proofs. Robert shows great interest in math on the eleventh night. On the twelfth night Robert and the Number Devil were invited to Number Heaven which concluded that his time with the Number Devil was ending. In Number Heaven Robert learns about Pi and he meets famous mathematicians like George Canto and Fibonacci, whom the Number Devil calls them Bonacci and Professor Singer. The story ends with Robert in class answering a question provided by his math teacher Mr. Bockel and thanking the Number Devil for helping him. A question that popped up for me was how did Robert all of a sudden dream of the Number Devil? If he kept on dreaming the same dreams over and over again how did he suddenly dream about something completely different from sliding down a never ending slide and being eaten by a giant fish? It was a very random way to start a story, but overall it was pretty interesting thing to read about.

4out of 5Yuta .–Count as 2 books (Review 3 and 4) I have read the book "The Number Devil" because my grandpa sent it to me from Japan in Japanese translation. The book was amazing. This book made me like math and this is when I first understood radicals and other mathematic things. I will tell you that, by the time you finish this book, you will think "Oh, math is so cool!". Characters In the book, Math Devil teaches math to this boy named Robert (Who hate Math),many interesting facts about math, and the secret be Count as 2 books (Review 3 and 4) I have read the book "The Number Devil" because my grandpa sent it to me from Japan in Japanese translation. The book was amazing. This book made me like math and this is when I first understood radicals and other mathematic things. I will tell you that, by the time you finish this book, you will think "Oh, math is so cool!". Characters In the book, Math Devil teaches math to this boy named Robert (Who hate Math),many interesting facts about math, and the secret behind it. In fact I never knew the fact that, "11 times 11 = 121, 111 times 111 = 12321, 1111 times 1111 = 1234321, 11111 times 11111 = 123454321" (Pg.23),creating a palindrome.(Any words, phrase, verse or numbers that can be read exactly same,from foreward or backward).In addition, the number devil talks about the pythagorean theorem, geometry, prime numbers, importance of one and zero, rutabaga etc. (rutabaga is the real way to say square root) There is way more interesting information about math than what I just mentioned. In fact, do people know what fibonacci numbers are? Probably, only those "math person" search for fibonacci numbers, and I didn't really know it until I read this book. (It explaines fibonacci numbers using diagrams and picture so even a small boys and girls can read this book). Conclusion This book taught me that, there is so much inside math. You might think that you know math, you might be thinking too shallow. This can be connected to anything, not just math. You have so many information in which you don't know, in this world. Recommendation This book, as mentioned, is written in large font. Although this book isn't that complex, it has so much inside. I recommend it to anyone from 4th to 9th grade.

4out of 5Steven–I really enjoyed The Number Devil. I thought that it was a worthwhile book and if you are having trouble in math, it can really help you. I thought that the book was very good in its way of delivering the information. Robert, the main character, is always asleep when he is with the Number Devil and in his dream world, math is completely different from ours. One thing i didn't really like about the book is how they do not always use real math terms. They use words like coconuts and rutabagas and I really enjoyed The Number Devil. I thought that it was a worthwhile book and if you are having trouble in math, it can really help you. I thought that the book was very good in its way of delivering the information. Robert, the main character, is always asleep when he is with the Number Devil and in his dream world, math is completely different from ours. One thing i didn't really like about the book is how they do not always use real math terms. They use words like coconuts and rutabagas and such to describe real mathematical methods. I wish that Hans Magnus Enzenzberger had just used real math terms and not fake things to talk about the math. However, after you finish the book they do acknowledge that the words they used in the dream world were not always real for math terms and that people wouldn't understand what your saying. Enzenberger actually had a whole section at the end dedicated to the mathematics covered in the book, and some that weren't, with the real word for the term if it was a word that was used in the dream world and not in the real world. Overall, The Number Devil was truly a mathematical adventure and is a worthwhile read for anybody interested in getting better in math or just for some fun.