Add Yahoo as a preferred source to see more of our stories on Google. Math shouldn’t be harder than finding the last matching sock in your laundry. These clever shortcuts convert head-scratching ...

You probably haven’t had to do longhand math in years, but you do mental math every day. Or maybe you google math problems ten times a day, because you’ve forgotten how to do any math beyond your ...

Start with a deck of cards. Before the trick, sneak a peek at the 10th card in the deck. Memorize it. Now choose a volunteer. Ask him to choose a number between 10 and 20. Count out that number of ...