See Ya Later Calculator

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