El diablo de los números by Hans Magnus Enzensberger | Goodreads
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El diablo de los números

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A Robert no le gustan las Matemáticas, como sucede a muchas personas, porque no las acaba de entender. Pero una noche él sueña con un diablillo que pretende iniciarle en la ciencia de los números. Naturalmente, Robert piensa que es otra de sus frecuentes pesadillas, pero en realidad es el comienzo de un recorrido nuevo y apasionante a través del mundo de las Matemáticas. ¿No es extraño hallar siempre secuencias numéricas por la simple multiplicación de los unos: 1 x 1 = 1, 11 x 11 = 121, 111111 x 111111 = 12345654321, y así en adelante? Y esto es sólo la operación más sencilla. Durante doce noches, Robert sueña sistemas numéricos cada vez más increíbles. De pronto, los números cobran vida por sí mismos, una vida misteriosa que ni siquiera el diablo puede explicar del todo. Nunca las Matemáticas habían sido algo tan fascinante. Pronto, el diablo le hará abandonar los tópicos escolares y hará que acceda a niveles superiores: ¡y aun así los entiende! Y el joven lector también. Los números, cada página que pasa, se van volviendo cada vez más absorbentes. Es como magia, y Robert quiere saber más y más hasta que, al fin, el diablo le hace comprender que algunos problemas y paradojas pertenecen a las altas esferas de la ciencia.

264 pages, Paperback

First published January 1, 1997

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About the author

Hans Magnus Enzensberger

304 books147 followers
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.

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5 stars
2,299 (33%)
4 stars
2,428 (35%)
3 stars
1,486 (21%)
2 stars
441 (6%)
1 star
164 (2%)
Displaying 1 - 30 of 746 reviews
Profile Image for Elaine.
107 reviews8 followers
October 7, 2012
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.
Profile Image for Lance Greenfield.
Author 155 books245 followers
February 24, 2016
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.
Profile Image for lorinbocol.
261 reviews372 followers
October 6, 2017
letto perché di me si potesse dire: nulla lasciò intentato.
peccato per il corollario: ogni tentativo fu vano.
Profile Image for David Madrigal.
20 reviews1 follower
December 8, 2014
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. 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.
Profile Image for Tung.
630 reviews44 followers
January 1, 2012
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.
Profile Image for Kelly (Maybedog).
2,925 reviews232 followers
October 28, 2015
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.
Profile Image for LaCitty.
872 reviews163 followers
November 20, 2019
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
This entire review has been hidden because of spoilers.
Profile Image for Bradman.
15 reviews16 followers
February 23, 2015
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.
Profile Image for Selene.
665 reviews177 followers
January 25, 2019
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.
Profile Image for Zahra Dashti.
402 reviews115 followers
April 26, 2015
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!
Profile Image for Anne Hamilton.
Author 47 books168 followers
April 6, 2013
...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.
Profile Image for Beth.
888 reviews4 followers
February 19, 2022
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!
Profile Image for Kelly Jahng .
500 reviews1 follower
June 18, 2017
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.
Profile Image for Jose Moa.
519 reviews72 followers
February 29, 2016
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
Profile Image for Ahmed Jaber.
Author 5 books1,710 followers
June 8, 2016

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
Profile Image for ramezan.
174 reviews39 followers
June 19, 2018
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-...
54 reviews
April 23, 2014
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.
Profile Image for José Luis.
268 reviews61 followers
February 6, 2015
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.
Profile Image for Dany Hdz.
103 reviews21 followers
April 8, 2018
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.
216 reviews1 follower
October 30, 2018
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!
Profile Image for Alberto.
280 reviews26 followers
March 19, 2020
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.
Profile Image for Jane.
2,682 reviews55 followers
July 25, 2018
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.
Profile Image for Anna.
407 reviews12 followers
January 23, 2021
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.
Profile Image for Muhajjah Saratini.
289 reviews10 followers
July 15, 2017
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~~~
Profile Image for Vicky Collar.
Author 1 book31 followers
September 9, 2017
Ha sido como volver a estudiar las matemáticas de primaria pero con un toque mucho más divertido. Creo que es muy buen regalo para niños en primaria para demostrarles lo curiosas que pueden resultar las matemáticas.
Profile Image for Greenglasses.
157 reviews
February 18, 2020
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.
Profile Image for Nurgül.
80 reviews3 followers
April 3, 2019
Herkesin hoşlanacağını zannetmediğim ama benim çok sevdiğim kitap. Okullarda okuma listelerinde olmalı kesinlikle.
Profile Image for Andy Cyca.
169 reviews25 followers
February 7, 2019
El mejor libro de matemáticas recreativas que no está escrito por un ruso ni por Martin Gardner!

En serio, este es uno de los mejores libros que he encontrado para explicar, de forma sencilla, un montón de curiosidades mentales que un chico o chica de unos 10 años podrá entender sin mucho problema. A cambio de su atención presenta un buen puñado de temas que alcanzan incluso las matemáticas «avanzadas» del siglo XX. Vale la pena, incluso para muchos adultos que se han declarado «malos para las matemáticas». Créanme, aquí hay mucho que descubrir y aprender.

La reseña termina aquí, voy a poner mi lista de los temas que trata el libro en su nombre académico y formal (en el libro casi no hay terminología avanzada).

En el libro hay:

1) Introducción a las matemáticas, construcción sistemática de números, cardinalidad de ℕ, hacia los infinitesimales mediante recíprocos, 11×11.
2) Números romanos, el cero y su importancia, notación posicional, potencias
3) División como «inverso» de la multiplicación, por qué no se puede dividir entre cero, números primos, criba de Eratóstenes, postulado de Bertrand o Teorema de Chebyshev, números pares como suma de dos primos, números impares como suma de tres primos (hacia la conjetura de Goldbach)
4) decimales «interminables» y quebrados, 0.999... es igual a 1, infinidad de números reales entre el 0 y el 1 (con prueba), decimales «repetidos», raíces, números irracionales y su cardinalidad, acercamiento a distintos infinitos
5) Números triangulares y la suma sucesiva de enteros, números como suma de triangulares, cuadrados como suma de triangulares, suma de números sucesivos y el truco de Gauss, otras «posibles figuras»
6) Sucesión de Fibonacci, sumas de números de Fibonacci, el problema de las liebres
7) Triángulo de Pascal y cómo codifica los triangulares y las potencias de 2 y la sucesión de Fibonacci, patrones con los números pares
8) Combinaciones, permutaciones (factoriales), selecciones a partir de un conjunto, aún más triángulo de Pascal
9) Cardinalidad de conjuntos infinitos contables, sumas infinitas de recíprocos, 1/2 + 1/4 + 1/8 +...=1, la serie armónica y su suma, prueba de la misma
10) Fi (ϕ) en Fibonacci y sucesiones similares, ϕ como fracción continuada, ϕ en el pentágono, ϕ=sqrt(5)/2, característica de Euler
11) Mostrar no es igual que probar, introducción a pruebas y axiomas, Johan van de Lune, vistazo a Bertrand Russell y el formalismo del«Principia Mathematica», el problema del viajante (travelling salesman) y problemas intractables
12) Russell y paradojas, Samuel Klein y superficies no orientables, Georg Cantor y números infinitos, Euler y Gauss, i=sqrt(-1), Pitágoras, π, regresa el truco de Gauss.



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