Four thousand years ago, the Babylonians invented multiplication. Last month, mathematicians perfected it. On March 18, two researchers described the fastest method ever discovered for multiplying two ...

19 is only 1 away from 20, so you prefer to start by multiplying 20 times 5, which equals 100. Then we need to take away a squadron of 5, because there are actually only 19 squadrons, not 20. 100 take ...

An area model is a rectangular grid that can help you solve multiplication problems. The process is similar to how you find the area of a rectangle. Two-digit numbers can be partitioned into smaller ...