See Ya Later Calculator

Book excerpt: The math book for anyone who thinks they hate math, full of easy, entertaining and practical tricks for mentally solving problems in seconds. No matter how much you might try to avoid numbers, we all use math every day to calculate a tip, figure out an interest rate, or estimate the cost of the groceries in your cart. But the good news is, math can be easy—and even fun—if you know how to do it all in your head. With these simple and downright magical math tricks, you can do everyday math faster than it takes to dig out your phone and find the calculator app. Step-by-step and easy-to-memorize directions show more than 125 math operations anyone can do in their head. Plus, it features do-it-yourself math projects, puzzles, and a bonus section for advanced mathophiles. Get ready to tackle problems such as . . . • How to easily square any number • How to add three-digit numbers • How to use a mirror to measure the height of a building • How to make a ruler out of a dollar bill • How to use geometry to paint walls, cut floor tiling, and do other home renovations • How to subtract numbers . . . by adding And lots more . . . No calculator required.