Elementary school students might memorize their times tables for single-digit numbers, but memorization won’t cut it when the teacher asks for three-digit multiplication. This requires an algorithm: students are taught to stack one number atop another and multiply each digit of the bottom number by each digit of the top one. For millennia, mathematicians believed this to be the fastest multiplication method, until a 23-year-old made a shocking discovery in 1960, which led to a mystery that remai...