Math Puzzles’ Oldest Ancestors Took Form on Egyptian Papyrus

New York Times (Pam Belluck)

I met a man with seven wives. ...”

You may know this singsong quiz,

But what you might not know is this:

That it began with ancient Egypt’s

Early math-filled manuscripts.

It’s true. That very British-sounding St. Ives conundrum (the one where the seven wives each have seven sacks containing seven cats who each have seven kits, and you have to figure out how many are going to St. Ives) has a decidedly archaic antecedent.

An Egyptian document more than 3,600 years old, the Rhind Mathematical Papyrus, contains a puzzle of sevens that bears an uncanny likeness to the St. Ives riddle. It has mice and barley, not wives and sacks, but the gist is similar. Seven houses have seven cats that each eat seven mice that each eat seven grains of barley. Each barley grain would have produced seven hekat of grain. (A hekat was a unit of volume, roughly 1.3 gallons.)

The goal: to determine how many things are described. The answer: 19,607.

The Rhind papyrus, which dates to 1650 B.C., is one of several precocious papyri and other artifacts displaying Egyptian mathematical ingenuity.