By Pamela Marx. Mathematical brainteasers increase in complexity as a reader—or a teacher leading a class—advances through the 35-plus challenges in this book. Topics include prime numbers, square numbers, tangrams, the four-color map problem, Jordan curves, the topology of knots, Alquerque, Sudoku, Egyptian multiplication, Plato's solids, Euler's Konigsberg bridge problem, Pascal's probability triangle, and Fibonacci's rabbits. Grades 5–8. Index. Bibliography. Glossary. Answer key. Illustrated. 8½" x 11". 136 pages.