The Secret of the Two Little Cups

In our imagined story, a young explorer found two little cups waiting on a wooden table. Beside them sat a bowl of smooth counting stones and a blank notebook. The evening was growing quiet, but the cups seemed to hold a secret. The explorer pulled up a chair and decided to find it.

Al-Khwarizmi was a mathematician who worked at the House of Wisdom in Baghdad.

The explorer imagined putting the same number of stones under each cup. Three more stones waited beside them. Eleven stones in all, said a note. The explorer did not lift the cups at once. It was more fun to make a drawing, leave room for a guess, and invite someone else to wonder too.

He wrote a book about solving equations. It showed how mathematics could help with everyday problems.