A 2021 Mathical Honor Book: "One of the best math teachers on the planet. His book is as buoyant, open-hearted, and energetic as he is." —Steven Strogatz, New York Times–bestselling author of Infinite Powers: How Calculus Reveals the Secrets of the Universe Why aren't left-handers extinct? What makes a rainbow round? How is a pancreas like a pendulum? These may not look like math questions, but they are—because they all have to do with patterns. And mathematics, at heart, is the study of patterns. That realization changed Eddie Woo's life—by turning the "dry" subject he dreaded in high school into a boundless quest for discovery. Now an award-winning math teacher and a YouTuber with nearly two million subscribers, Woo sees patterns everywhere: in the "branches" of blood vessels and lightning, in the growth of a savings account and a sunflower, even in his morning cup of tea! Here are twenty-six bite-size chapters on the hidden mathematical marvels that encrypt our email, enchant our senses, and even keep us alive—from the sine waves we hear as "music" to the mysterious golden ratio. This book will change your mind about what math can be. We are all born mathematicians—and it's a numberful world. "Introduces mathematical vocabulary in a fun and approachable way. . . . A gentle but enthusiastic introduction to a wide variety of interesting mathematical topics." —Mathematical Association of America "Lighthearted and delightful . . . the ideal guide to math's multi-patterned treasures." — Foreword Reviews Publisher's note: It's a Numberful World was published in Australia under the title Woo's Wonderful World of Maths.