50 Challenging Algebra Problems by Chris McMullen (affiliate link)
A to Z Mathematicians by Tucker McElroy, Ph.D.(affiliate link)
Big Ideas for Small Mathematicians Ages 6-11 by Ann Kajander (affiliate link)
The Cartoon Guide to Calculus by Larry Gonick (affiliate link)
Math Genius by Mike Goldsmith (affiliate link)
Math Labs for Kids by Rebecca Rapoport & J.A. Yoder (affiliate link)
Math Puzzles and Brainteasers Grades 6-8 by Terry Stickels (affiliate link)
