How Many Socks Make a Pair?: Surprisingly Interesting Maths

by Rob Eastaway

How many socks make a pair? The answer is not always two. And behind this question lies a world of maths that can be surprising, amusing and even beautiful.
Using playing cards, a newspaper, the back of an envelope, a Sudoku, some pennies and of course a pair of socks, Rob Eastaway shows how maths can demonstrate its secret beauties in even the most mundane of everyday objects.
If you already like maths youOll discover plenty of new surprises. And if youOve never picked up a maths book in your life, this one will change your view of the subject forever."

Genres: Nonfiction, Mathematics, Science, Popular Science

ebook

First published August 14, 2008

About the author

Robert Eastaway is an author who is active in the popularisation of mathematics. He is a former pupil of The King's School, Chester, England and has a degree in Engineering and Management Science from the University of Cambridge. He was President of the UK Mathematical Association for 2007/2008. Eastaway is a keen cricket player and was one of the originators of the International Rankings of Cricketers. He is also a former puzzle-writer for the New Scientist magazine and he has been involved in live mathematics shows on Virgin Radio (now Absolute Radio). He is the Director of Maths Inspiration, a national programme of maths lectures for teenagers which involves some of the UK’s leading maths speakers such as Simon Singh and Colin Wright.

Robert Eastaway's titles appear under the name "Rob Eastaway" in the UK and some other countries.

Reviews

[Baby Adam · Rating 5 out of 5]

Some really nice material in there, and very well presented. I'd like to give it five stars, but I found a few things somewhat #triggering in a highly enjoyable and inspiring miscellany:

(i) Eastaway presents the fact that x^0 =1 as a mathematical convention, and hence misses the point that it makes sense. The number system would not run anywhere near as smoothly with any other choice for the value of x^0.

(ii) A rounding error, come on!

(iii) When talking about infinity, the "1-1+1-1+1-1+1-..." series is discussed, and the fallacious argument showing that the value of the sum is 1/2 is presented. However, Eastaway makes the #outrageous claim that "there are mathematicians who believe 1/2 is the best answer" #lolnope

I'd definitely recommend this book, so do not be put off, although I very much enjoyed ranting about some rather minor points.

[Maddy · Rating 3 out of 5]

This book had some interesting points but also felt patronising at times.

It was also frustrating that the way many chapters went seemed to be “hey look at this really cool thing that happens, and the reason that this happens is because of maths”. Well ok... WHAT maths? It stopped just before it got interesting.

I think I went into this book with the wrong understanding of who it was aimed at. It might be well suited to spark an interest in maths for someone who doesn’t think they like it or perhaps for some children, but if you’re actually already interested in the subject it’s probably not for you.

[Caleb Thorne · Rating 3 out of 5]

Interesting topics but doesn't go very deep. I was left wanting more.

[Nick · Rating 5 out of 5]

I enjoyed this book. It has a lot of neat observations, and it's separated into chapters, where if you're not interested in a particular chapter, you can skip over it.

To give you an example, I'll show one of the puzzles from the book:

"Two trains are approaching each other on the same track, each traveling at 50 mph. When the trains are 100 miles apart, a fly that always flies at 60mph, sets off from the front of Train A directly toward the oncoming Train B. When it gets to Train B it turns around and heads straight back towards A, and it continues to fly back and forth between the two trains until CRUSH! the two trains smash into each other, crushing the fly in the process.

How far did the fly fly - before it met its unfortunate end?"

There are two ways of solving the problem - one involving taking the limit of a geometric series, and the other is a simple and elegant solution. If you enjoy brain teasers like this, you'll enjoy this book.

[Jeff Duda · Rating 5 out of 5]

Great short read on the true spirit of mathematics - a mix of practical and theoretical. So many good examples to teach people math at many levels of intensity and rigor!

The references are mostly suited towards a UK audience, so this American reader was somewhat unfamiliar with some of the examples.

[Pashmina · Rating 4 out of 5]

Very interesting, but in my case, not so surprisingly. (I love maths!)

[Lucy Pallent · Rating 3 out of 5]

Too basic to recommend to anyone above the age of 14. A fantastic intro book for younger readers with an interest in numbers.

[Andy Venn · Rating 4 out of 5]

This is a pretty good popular maths book. Well written, lots of tips and shortcuts. One of those books you can easily dip in and out of.

[Omkar Shelar]

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[Dominika · Rating 4 out of 5]

Great book filled with interesting math problems, but not for those who actually like math - solutions are not explained so everything you learn is quite shallow. You may impress your friends with some neat math facts, but you won't be able to answer "why?". I expected a little more, but that's not what this book is. But for what it is, it's a very well-written and entertaining book, easy and pleasant to read, I would recommend.

[Nurture Waratah · Rating 3 out of 5]

This book is full of interesting maths facts, card tricks, word problems and other fun facts and puzzles. Every chapter had something new for me to learn, not all of which would be traditionally viewed as mathematics by the average layperson. I found this book both fascinating and incredibly informative and I recommend it to anyone with the slightest interest.

I should warn you, though, some of the chapters will definitely make your brain hurt - especially the chapter about infinity!

[Roger · Rating 4 out of 5]

This is a well written and very entertaining book, full of interesting facts and observations, and with some challenging puzzles thrown in. It's a great book to dip into and it contains some tricks that you could try out on family or friends. It won't turn you into a mathematician but it might make you think.

[Carmila · Rating 4 out of 5]

Who said mathematics couldn't be fun? This book is very different from what I generally read but I really enjoyed it. The authors show us how maths are everywhere in our daily lives and proceed with understandable - and often funny - explanations. You don't need to be a math genius to get it and you do learn a lot.

[Andrew · Rating 4 out of 5]

Interesting enough, well-written and easy to read.

Although I recognised some of the "popular maths" material as topics I already knew, there were enough surprises here for it to be worth reading.

[James Webster · Rating 3 out of 5]

An interesting and entertaining read which does give some Ah, Aha! and Haha of Maths, as promised. Eastaway doesn't get into detailed e plantations but, even for a non-mathematician like me, it's a bit frustrating always to have to take his word for it.

[Webfrau · Rating 3 out of 5]

It wasn't gripping reading but there were some interesting and amusing maths tricks and quirks in this book.

[Dana.g]

interesting so far, light and easy style to make you think out of the box.

[Voracious · Rating 3 out of 5]

I enjoyed this, and it's right up D's street. So, recommended for 10 year olds who think maths is really cool. :)

[Robert Drummond · Rating 4 out of 5]

Interesting little book on day to day maths...

[Igor · Rating 4 out of 5]

Divertente e rapido da leggere, esplora alcune curiosità matematiche in modo molto divulgativo ma avvincente.

[Jose · Rating 3 out of 5]

Amusing!