The Number Devil: A Mathematical Adventure

by Hans Magnus Enzensberger, Michael Henry Heim (Translator)

Twelve-year-old Robert hates his maths he sets his class boring problems and won't let them use their calculators. Then in his dreams Robert meets the Number Devil, who brings the subject magically to life, illustrating with wit and charm a world in which numbers can amaze and fascinate, where maths is nothing like the dreary, difficult process that so many of us dread. The Number Devil knows how to make maths devilishly simple.

Genres: Mathematics, Fiction, Fantasy, Childrens, Young Adult, Education, German Literature

264 pages, Paperback

First published January 1, 1997

About the author

See also:
Cyrillic: Ханс Магнус Енценсбергер

Hans Magnus Enzensberger was a German author, poet, translator and editor. He had also written under the pseudonym Andreas Thalmayr.

Enzensberger was regarded as one of the literary founding figures of the Federal Republic of Germany and wrote more than 70 books. He was one of the leading authors in the Group 47, and influenced the 1968 West German student movement. He was awarded the Georg Büchner Prize and the Pour Le Mérite, among many others.

He wrote in a sarcastic, ironic tone in many of his poems. For example, the poem "Middle Class Blues" consists of various typicalities of middle class life, with the phrase "we can't complain" repeated several times, and concludes with "what are we waiting for?". Many of his poems also feature themes of civil unrest over economic- and class-based issues. Though primarily a poet and essayist, he also ventured into theatre, film, opera, radio drama, reportage and translation. He wrote novels and several books for children (including The Number Devil, an exploration of mathematics) and was co-author of a book for German as a foreign language, (Die Suche). He often wrote his poems and letters in lower case.

Enzensberger also invented and collaborated in the construction of a machine which automatically composes poems (Landsberger Poesieautomat). This was used during the 2006 Football World Cup to commentate on games.

Tumult, written in 2014, is an autobiographical reflection of his 1960s as a left-wing sympathizer in the Soviet Union and Cuba.

Enzensberger translated Adam Zagajewski, Lars Gustafsson, Pablo Neruda, W. H. Auden and César Vallejo. His own work has been translated into more than 40 languages.

Reviews

[Elaine · Rating 2 out of 5]

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.

[Alaska Lee · Rating 4 out of 5]

”Se calcula solo”… Tan bonito pero sobre todo, tan útil que me gustaría poder viajar en el tiempo para darle a mi yo de 11 años este libro y que su relación con los números cambia para siempre. Tienen que dárselo para leer a sus niños (o niños cercanos a ustedes), no tienen idea de cuánto lo agradecerán.

[Lance Greenfield · Rating 4 out of 5]

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.

[lorinbocol · Rating 3 out of 5]

letto perché di me si potesse dire: nulla lasciò intentato.
peccato per il corollario: ogni tentativo fu vano.

[David Madrigal · Rating 5 out of 5]

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. 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. 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.

[Noam · Rating 4 out of 5]

So much fun! 😊

If you place this book under your pillow at night, the Number Devil will appear in your dreams and teach you all sorts of amazing things about numbers, just as he did in his conversations with Robert, the young protagonist of this book.

I guess I hear you thinking: Numbers? What’s so fascinating about numbers? I certainly don’t want to spoil your pleasure of reading this book, but here are just a few small examples, just between us 😉

Have you ever heard of the Fibonacci sequence? It’s a sequence of number in which each element is the sum of the two elements that precede it. If you start with 1 and 1 the next one will be 2 (because that’s 1+1), the one after that will be 3 (because that’s 1+2) etc. The result is the sequence 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233 etc. etc. Simple, isn’t it? Now the amazing thing is that the Fibonacci sequence can be found in endless places in nature, including in how the seeds of a sunflower are arranged and how the structure of shells is designed.

May I ask you a personal question? Do you like rabbits? I’m sure you do. Now imagine you get a pair of rabbits. At the end of the first month, they mate, but there is still only 1 pair. At the end of the second month, they produce a new pair, so there are 2 pairs of rabbits now. At the end of the third month, the original pair produce a second pair, but the second pair only mate, so there are 3 pairs in all. At the end of the fourth month, the original pair has produced yet another new pair, and the pair born two months ago also produces their first pair, making 5 pairs in total etc. How many pairs of rabbits do you have each month? 1 in the first, 1 in the second, 2 in the third, 3 in the fourth, 5 in the fifth etc. Bingo: That’s the Fibonacci sequence! 😊



The rabbits of Fibonacci (Wikimedia Commons)

Another example: Imagine having a drawing consists of lines, nodes and maybe one or more surfaces surrounded by lines and nods. . Just think of shapes like:



or maybe:



(Images from Wikimedia Commons)

Let’s take as an example the upper left shape of the first drawing. It consists of 4 nodes, 6 lines and 3 surfaces between them. You’re still with me? Now if you add to the number of nodes (4) the number of surfaces (3) and deduct the number of lines (6), the outcome is 1. Correct? And here comes the magic: That’s always the case! No matter the shape you choose, if you add to the number of nodes the number of surfaces and deduct the number of lines the result is always 1! Try calculating this for each of these shapes or any shape you can draw!

These are just two of the many fascinating examples in this book. Curious to know more? Read the book, or leave it under your pillow. 😉

This book is inspiring. It’s funny, surprising, and—much like Harry Potter—it’s magic! It includes marvelous mathematic tricks, some highly practical and others completely pointless, yet they’re all utterly fascinating! It’s an original, creative, witty, and uninhibited book. It reveals the great beauty behind many well-known (and lesser-known) mathematical principles and phenomena. Hans Magnus Enzensberger can explain very complex issues in a very simple way. The beautiful illustrations of Rotraut Susanne Berner bring the Number Devil and his world to life.

This book was written for children at the age of 9 to 99 so it suits my age. I really enjoyed it, even though the subtitle mentions it is intended for anyone who is afraid of mathematics. I’m not. I enjoyed mathematics immensely when I was, well, let’s say: as old as Robert. This book certainly makes me feel like reading more books about mathematics once again…



Just one of the many beautiful illustrations of this book. This one is from the English edition which is published by McMillan Publishers

Quotes

'- Wer bist denn du?, fragte Robert.
Der Mann schrie ihn überraschend laut an:
- Ich bin der Zahlenteufel!
Aber Robert hatte keine Lust, sich von einem solchen Zwerg etwas gefallen zu lassen.
- Erstens, sagte er, gibt es gar keinen Zahlenteufel.
- So? Warum redest du dann mit mir, wenn es mich überhaupt nicht gibt?
- Und zweitens hasse ich alles, was mit Mathematik zu tun hat.
- Warum denn das?
- Wenn zwei Bäcker in sechs Stunden 444 Brezeln backen, wie lange brauchen dann fünf Bäcker, um 88 Brezeln zu backen? So ein Blödsinn, schimpfte Robert weiter. Eine idiotische Art, die Zeit totzuschlagen. Also verschwinde! Hau ab!' p.11-12

'- Setz dich doch, Robert, sagte der Zahlenteufel. Diesmal war er überraschend freundlich.
- Wo denn? Auf einem Pilz?
- Warum nicht?
- Das ist doch albern, beschwerte sich Robert. Wo sind wir hier überhaupt? In einem Kinderbuch?' p.30

'Noch ganz benommen sagte er zu seiner Mutter:
- Weißt du, wann ich geboren bin? 6 x 1 und 8 x 10 und 9 x 100 und 1 x 1000.
- Ich weiß nicht, was mit dem Jungen los ist in letzter Zeit, sagte Roberts Mutter, schüttelte den Kopf und hielt ihm eine Tasse Kakao hin.
- Damit du wieder zu Kräften kommst! Du redest ja ganz wirres Zeug.
Robert trank seinen Kakao und hielt den Mund. Alles, dachte er, kann man seiner Mutter unmöglich erklären.' p.46

'- Ja, mein Lieber, manchmal frage ich mich selber, wo die Mathematik aufhört und die Hexerei anfängt.
- Phantastisch. Hast du das eigentlich alles erfunden?
- Nein.
- Wer denn?
- Weiß der Teufel!' p.142

'Ach ja, sagte sich Robert, es ist immer dasselbe. Im Traum kriegt man die besten Torten zu essen, und wenn man Glück hat, bekommt man sogar einen goldenen Stern um den Hals gehängt, aber kaum ist man aufgewacht, ist alles wieder weg.
Als er aber im Schlafanzug im Bad stand und sich die Zähne putzte, kitzelte ihn etwas auf der Brust, und als er nachsah, fand er dort einen klitzekleinen fünfzackigen Stern an einem dünnen goldenen Kettchen.
Er konnte es kaum glauben. Diesmal hatte das Träumen wirklich etwas gebracht!' p.249-250

[Carduelis · Rating 4 out of 5]

On iki-on sekiz civarında yaş aralığına çok uygun; matematiği sevenlerin bayılacağı, sevmeyenlerin bile ilgisini uyandırabilecek, resimli anlatımıyla keyifli bir kitap Sayı Şeytanı.

Kitap, Robert ile Sayı Şeytanı arasında geçen on iki gecelik sohbetlerden oluşuyor. Her gece Sayı Şeytanı Robert'i ziyaret ediyor ve matematiksel düşünme becerisi ile ilgili konularda fikir yürütüyorlar. Sayı korkusu, sonsuzluk fikri, doğadaki düzen, düzenleme biçimleri olasılıkları, üstel büyüme, bölünemeyen sayılar, sayıların geometrik karşılığı, işlemleri tersine çevirme, bütünlük ve dönüşüm gibi farklı matematik fikirleri üzerine konuşuyorlar. Yaz tatili için güzel bir seçenek.

Herkese keyifli okumalar.

[Tung · Rating 1 out of 5]

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.

[Kelly (Maybedog) · Rating 2 out of 5]

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.

[Bradman · Rating 5 out of 5]

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.

[LaCitty · Rating 4 out of 5]

Romanzo graziosissimo che racconta in modo semplice, intelligente e divertente alcuni concetti matematici di base (ma non solo). Col pretesto dei sogni/incubi di Roberto, viene introdotto il Mago della Matematica che, con i suoi trucchi, spiega alcune regole e formule con esempi di facile comprensione per grandi e piccini. Consigliato per chi si deve riconciliare con questa materia un po' ostica

[Selene · Rating 4 out of 5]

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.

[Zahra Dashti · Rating 4 out of 5]

خیلی کتاب خوبی بود. اگه ریاضیات و بازی با اعداد و این تیپ چیزها رو دوست دارین بخونیدش. مخصوصا برای نوجوانها عالیه. دنیای زیبایی رو براشون از اعداد به تصویر می کشه و به شیوه شیرینی بهشون اطلاعات می ده در مورد علم اعداد و ریاضیات.
با اینکه از سن من گذشته بود وقتی خوندمش ، ازش خیلی لذت بردم!

[Anne Hamilton · Rating 5 out of 5]

...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.

[marco renzi · Rating 3 out of 5]

Ammetto di averlo letto fuori tempo massimo. Forse, verso i dodici-tredici anni, avrebbe davvero fatto il suo lavoro.
Difficile invece, a trentasei, apprezzare la matematica attraverso questo libro, anche se la parte della disciplina qui affrontata mi è sempre piaciuta e mi affascina tuttora; e a dire il vero, era pure quella che un po' mi salvava dalla stupidità.

Perché l'ho letto? Una collega coraggiosa me lo ha consigliato.
Mi è piaciuto? Sì; con le riserve di cui sopra, che non sono colpa del libro e né del suo autore, che naturalmente si rivolge a un altro pubblico, per quanto lo si possa comprendere e apprezzare pure da adulti; specie se il conflitto con la matematica, come nel mio caso, non si è ancora del tutto risolto.

[Kelly Jahng · Rating 3 out of 5]

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.

[Jose Moa · Rating 4 out of 5]

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

[Ahmed Jaber · Rating 4 out of 5]

هذا كتاب لطيف خفيف وأحببته حقاً.

العفرتة إن كانت فستكون في الرياضيات، كتاب يحرّك العقل بسحر الأرقام.
قصة روبرت مع عفريت الأرقام الذي يحبّب له مادة الرياضيات بطرقه العجائبية.

مجرد عمليات حسابية بسيطة ستقودك إلى عوالم داخل الأرقام تجعلك تدور وتدور وتدور.

أراه متوسط الجودة للأطفال، وفائق الروعة لمن هم على الأقل يحبون الرياضيات ولو من بعيد.
بالنسبة لي، استمتعت بكل جزئية فيه، وعلمت أشياء لم أكن أعرفها قبل قراءتي للكتاب رغم ممارساتي وحبي للرياضيات، والحساب

[Beth · Rating 5 out of 5]

Review: https://hiplibrariansbookblog.com/200...

[ramezan · Rating 4 out of 5]

خلاصه:
رابرت (مثل خیلی از بچه‌های دیگر) از ریاضی متنفر است. او که مدام خواب‌ها و کابوس‌های عجیبی می‌بیند، در یکی از این خواب‌ها با موجود شگفت‌انگیزی مواجه می‌شود که خودش را عدد شیطان می‌نامد. او و عدد شیطان به مدت دوازده شب به قلمروهای زیبا و جذاب ریاضی سرک می‌کشند: اعداد اول، سری‌های فیبوناچی، اعداد مثلثی، ترکیبیات و...

درباره کتاب:
یکی از فرق‌های ریاضی با علوم دیگر انتزاعی بودن آن است. برای همین علی‌رغم کتاب‌های جذاب زیادی که مختص کودکان و نوجوانان نوشته شده‌اند، کتاب‌های کمتری می‌بینید که با این نیت نوشته شده باشند که کودکان را با ریاضی آشتی بدهند (برای نمونه می‌توانید این را ببینید). عد شیطان قطعا در ماموریتی که برای خودش در نظر گرفته است موفق شده‌است:
*سطح مطالب بیان‌شده طوری در نظر گرفته شده‌است که تقریبا برای تمام بچه‌های پنجم دبستان به بالا قابل فهم است؛
*این کتاب داستان دارد! یعنی این‌طور نیست که صرفا یک‌سری مفهوم ریاضی را به صورت قصه‌وار به هم چسبانده باشد؛
*مفاهیم ریاضی مطرح شده واقعا دست‌چین شده‌اند: هم جذابند، هم در محیط اطراف قابل مشاهده‌اند و هم کودک می تواند پس از چند قدم جلو جلو برای خودش خواصی را کشف کند؛
*با مشارکت دادن شخصیت اصلی (و به تبع آن مخاطب) در اکتشافات به کودکان اعتماد به نفس می‌دهد؛
*حالتی رازآمیز برای کودک ایجاد می‌کند که باعث می‌شود فکر کند به اطلاعاتی سری و ارزشمند دست یافته‌است.

نکات:
کلا یکی از جذاب‌ترین تجربه‌های کتاب‌خوانی من در دوران دبستان و راهنمایی بود.
نیاز به دانش اولیهٔ ریاضی در حد ریاضیات سوم-چهارم دبستان زمان ما دارد!
چندین بار هم بدون هیچ بار ایدئولوژیکی از لفظ شیطان (یا در بعضی ترجمه‌ها جن!) استفاده شده.

http://davanevis.blog.ir/post/number-...

[Jason · Rating 1 out of 5]

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.

[José Luis · Rating 4 out of 5]

https://30dediferencia.wordpress.com/...

No creo que leer El diablo de los libros pueda hacer que un niño al que no le gusten las matemáticas empieza a apreciarlas, pero estoy convencido de que no era esa la intención del autor al escribir el libro, sino más bien crear una historia entretenida con las matemáticas como hilo argumental en la que se nos muestran curiosidades y aspectos llamativos de las mismas que puedan despertar posteriormente el interés de los chavales.

Me ha resultado muy curiosa la licencia que se toma el autor de cambiar algunos términos matemáticos, como la serie de Fibonacci, las raíces cuadradas, las potencias o los factoriales y aunque entiendo que algún purista pueda sentirse molesto al final del libro encontramos las explicaciones precisas y tampoco hay que darle más importancia de la que tiene.

En resumen una historia entretenida, quizás algo tediosa en algunos momentos porque quizás uno esperara un poquito más de acción, y que puede estar bien para chavales a partir de 10-11 años que quieran encontrar cosas curiosas en el mundo de las mates.

[Dany Hdz · Rating 4 out of 5]

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.

[May · Rating 4 out of 5]

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!

[Alberto · Rating 3 out of 5]

Erano secoli che io e Benedetta dovevamo leggere insieme questo libro, e da qualche tempo lei continuava a dire che dovevamo proprio deciderci. Finalmente abbiamo trovato la voglia e il coraggio di affrontarlo, e devo dire che, soprattutto nella prima parte, ne e' proprio valsa la pena!

Ci siamo divertiti a guardare la matematica da una prospettiva un po' differente, molto giocosa, anche a ridere per il fatto che le sue reazioni erano spesso esattamente uguali a quelle di Roberto, il ragazzino protagonista della storia! Alle prese con la matematica i bambini reali e quelli immaginari si comportano allo stesso modo!

La cornice non e' sempre all'altezza forse, soprattutto nella seconda parte, ma tutto sommato si va avanti, e chissa' che adesso la matematica sara' guardata con occhio piu' benevolo dalla mia principessa.

[Jane · Rating 1 out of 5]

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.

[Santiago Ortiz · Rating 5 out of 5]

I liked it, kid loved it, he says he wants more math.

[Anna · Rating 3 out of 5]

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.

[Superisa · Rating 5 out of 5]

Hay libros que explican las matemáticas… y hay libros que consiguen algo mucho más difícil: despertar curiosidad por ellas. Eso es lo que pasa con El diablo de los números, de Hans Magnus Enzensberger.

Mientras lo leía pensaba muchas veces en ese momento tan especial en el que algo que parecía complicado de pronto se entiende y aparece esa mezcla de sorpresa y satisfacción. El libro tiene justo esa capacidad: explicar ideas matemáticas de forma sencilla, casi como si alguien te estuviera contando una historia antes de dormir.

Por eso me parece una lectura maravillosa para chicos y chicas a partir de 12 años, justo cuando empiezan a encontrarse con las matemáticas a un nivel un poco más exigente. No solo ayuda a entender conceptos, también puede despertar algo mucho más valioso: la curiosidad por los números y el placer de pensar.

Ojalá más estudiantes se encontraran con un libro así en el momento adecuado. Porque a veces basta una historia bien contada para que alguien descubra que las matemáticas no solo se entienden… también pueden llegar a enamorar.

[Muhajjah Saratini · Rating 3 out of 5]

Membuktikan bahwa tidak ada bukti adalah bukti itu sendiri.--p. 240

Buku ini nggak santai, lumayan buat pemanasan.

Saya menyarankan untuk yang menyukai matematika untuk membacanya. Ini, lho, ada novel yang beneran bahas perkara angka2 dengan balutan cerita.
Di buku ini, ceritanya yang jadi pemanis, matematika yang utama.

Review lengkap menyusul~~~