Mental Math Challenges Author:Michael L. Lobosco Imagine guessing someone's age with just three simple questions, totaling up any five shopping items faster than a calculator, or changing the color of a toothbrush in a flash. You can--with these colorful math challenges. All you need are some readily available materials, a sense of fun, and the desire to experiment. Do instant calculations and... more » mind reading, vanishing tricks and illusions, precision measuring without instruments, and solitaire pastimes. Create beauty with circles and flexagons--and make a terrific paperweight with a tetrahedron! With just a little patience and effort, you'll meet every one of these challenges. 80 pages (all in color), 8 1/2 x 10. NEW IN PAPERBACK« less