Sunday, June 8, 2014

The Joy of X

"Did O.J. do it? How should you flip your mattress to get the maximum wear out of it? How does Google search the Internet? How many people should you date before settling down? Believe it or not, math plays a crucial role in answering all of these questions and more." (Goodreads summary)

When researching which book to pick for this project, this is one of the things that caught my attention. Math really is all around us and The Joy of X draws this out. 

The book has six parts, each presenting certain elements of mathematics: Numbers, Relationships, Shapes, Change, Data, and Frontiers. Sounds intimidating but these sections represent a tour through the history and development of mathematics, including the practical applications. Never again will I fall into the trap of bungling the answer to the classic "If three men paint three fences in three hours, how long will it take for one man to paint one fence?" (answer: 3 hours). Now I understand why a piece of paper can't be folded in half more than 7-8 times, and how a high school junior was able to beat the record using a monstrously long roll of... toilet paper! I know how Luke could guarantee himself a win over Darth Vader in a game of laser tag (hint: it involves a conic section). For young lovers, mathematics could help in finding the perfect mate (if you make a few simplistic assumptions, that is). And if the prosecution in the O.J. Simpson murder trial had understood probability and statistics, could they have gotten a conviction?
The Joy of X covers a lot of math. This is a book that progresses from simple number theory, e.g., what do we mean when we say we have six of something? to basic arithmetical operations (adding, subtracting, multiplication, division) to discussions of fractions, and percentages. There are chapters explaining basic algebra, and how often we use the theory of solving for X without even realizing it. Next up is Geometry, the theory of infinity, negative numbers--Strogatz covers them all and then marches through integral calculus (here it started to become a bit more difficult ), differential equations, and vector analysis.

As enjoyable as the first five sections of the book were, my favorite section was the last, "Frontiers," where the author covered topics including prime numbers, where I learned that no one has ever found an exact formula to find primes; group theory, which bridges the arts and sciences; topology; spherical geometry; and infinite series. This section presented some fascinating ideas. For example, group theory suggests how to get the most even wear from a mattress and confirms the old mnemonic "spin in the spring, flip in the fall." For topology, the famous Möbius strip is examined. I thought I understood the properties of a Möbius strip, but they're actually more remarkable than I would have guessed. And the most mind-blowing concept was that some infinities are larger than others. This finding, which was bitterly contested at the time, is brilliantly demonstrated with a parable named the Hilbert Hotel.Sounds intimidating but the readings were so interesting that it never felt cumbersome. The author, Steven Strogatz, writes in a way that is almost engaging and no where near dry, like you think a math book would be.

The later chapters are definitely more advanced, but if you manage to stick it out that far, you'll be rewarded with an esoteric but lilting discussion of number theory.

The book, however, is simple. Think of dipping your toes in the water versus plunging into it. It brings to light some concepts that you might have always wondered about but it never really dives deep into any one topic, really explaining in depth the concepts. This is good, in my opinion though, because for those reading, math might not be that fun for them. Too much explanation could turn them off. The reader is able to get a general idea, maybe an 'ah-ha' moment or two, move on to another topic or explore more using the notes section Strogatz provides at the end of the book.

I would recommend this book to a wide range of people. Just because the book is about math doesn't mean you have to be interested in math to read it. The real world tie ins are appeasing to all, which is probably one of my favorite qualities of this book.

I would also like to somehow incorporate some of his explainations into my own explanations when teaching. Strogatz is able to explain in a simple matter that may be useful for others.

Check out the book trailer to get a look at the book and the author!


  1. Alissa, I love your book review of The Joy of X. Your writing reminds me of
    Strogatz's writing - whimsical and fun to read! Your review would make me want to read the book, if I hadn't already read it! I enjoyed the book, too. Great job!

  2. Good coverage and a nice review. I found it very applicable to teaching, too. 5C's +