If there’s a kind of puzzle not included in this incredibly varied collection, we can’t imagine what it is. There are math problems, lateral-thinking conundrums, brain teasers, whodunits, IQ tests, trivia quizzes…as well as an assortment of baffling optical illusions and amazing stunts using paper, scissors, and other items found around the house. It’s nonstop fun, but every one of these challenges will enhance real-life problem-solving skills. If you wrote down all the numbers from 1 to 100, how many times would you write the number 3? How old do you have to be to become a U.S. Senator? What 11-letter word is pronounced incorrectly by more than 99% of Ivy League graduates? (Answers: 20, 30, incorrectly. )