Is That a Big Number? is an easy but excellent read for the person who wants to understand large numbers in context of everyday life. Sprinkled throughout the text are what Elliott calls “landmark numbers,” which are used as comparison numbers for the associated text. These landmark numbers (with concepts ranging from the length of the Amazon river, the maximum load a person can carry in their arms, and the percentage of people living in extreme poverty in 2015) are easy ways for the author — and the reader — to conceptualize how large or small a number may be. A key tenet of this book is the idea of comparison: every example the author provides is stacked against a well-known fact. Every chapter ends with a list of (approximate) relations to help the reader grasp magnitudes of heights, distances, weights, and riches.
A particular concept that stood out to this reviewer was the way in which the author didn’t just give the relations between a particular number and its landmark pair; Elliott guided the reader through the method of approximating. Visuals smattered through text include timelines, graphs, and graphics superimposed on an image (p. 81, used for estimating seats in an arena). Each visual was relevant to the surrounding text and served to help the reader understand a concept relative to a landmark number.
Is That a Big Number? concludes with a discussion of the Millennium Declaration, a set of eight international development objectives. With the understanding of numbers developed through text, Elliott approaches each of these goals and associated targets with a measuring eye. Each target is assigned an achievement level, but more helpful is the reasoning the author gives behind assigning that level. This reasoning gives a sense of what has been done and what remains, and in some sense, puts the onus on the reader to go the next step, using the five visualization techniques provided through the book, to change the world for the better.
Megan Sawyer is an associate professor of mathematics at Southern New Hampshire University in Manchester, NH.