New and Noteworthy Titles on our Bookshelf

The Price of Cake: And 99 Other Classic Mathematical Riddles

By Clément Deslandes and Guillaume Deslandes. The MIT Press, 2023, 215 pp.

Courtesy of the MIT Press.

I suspect many mathematicians have a long history of solving puzzles. There is a distinctively satisfying moment when a puzzle that has challenged your mind for a minute, an hour, a day, or a week is solved. The recent publication The Price of Cake contains 100 inviting and irresistible mathematical riddles and puzzles. The book is ordered not by mathematical knowledge required but by the complexity of solutions, and it contains both familiar and uncommon riddles.

The puzzles make use of the pigeonhole principle, binomial coefficients, equivalence relations, bijections, permutations, induction, congruences, binary expansions, and probability. I expect that many readers could solve the riddles without formal training in mathematics. However, being familiar with these topics provides an advantage, and so there is a brief section at the end of the book that covers the mathematical themes.

I found great fun in the riddles “A Kangaroo on a Staircase,” “The Rats and the Bottles,” and “Linking the Edges.” I think this book would be a great addition to your personal collection of riddles and would be useful when considering puzzles for a math club meeting. As the supplementary mathematics material in the book points to specific riddles, you could even use some of the riddles to enhance your teaching of one of the covered topics.

For the Recorde: A Welsh History of Mathematical Greats

By Gareth Ffowc Roberts. University of Wales Press, 2023, 160 pp.

Courtesy of University of Wales Press.

While this is a history of mathematics book, its focus is unique: Welsh mathematicians who lived during the period from the 16th to 20th century, along with descriptions of prominent locations in Wales at the time. The narrative is lively and offers enough variety to hold a reader’s attention, including tales of scandals and mathematicians’ travels outside of Wales as well as stories of familiar (non-Welsh) mathematical people and places, such as Pythagoras and Gauss. I was delighted to find that puzzles are sprinkled throughout the text, though some take the form of short mathematical calculations rather than puzzles. In addition, the author includes enough personal anecdotes that the book is part memoir.

The title of the book refers to the Welsh mathematician who used the first known instance of the equals sign, Robert Recorde. The book reveals other “mathematical firsts” credited to Welsh mathematicians; for instance, it details the first mathematician to use $\pi$ to represent the ratio of the circumference to the diameter of a circle and the development of the first insurance policies and their associated mathematics.

This book will be of interest to mathematicians who appreciate learning historical tidbits for their own enjoyment or to include in their courses. It could supplement a history of mathematics course or provide extra historical context in other math courses. This book is a welcome addition to historical literature not only because it informs the community about mathematical greats from Wales, but also because it adds to the growing inventory of mathematical contributions from a diverse group of people. This was a fun read that I think many mathematicians would enjoy.