The St. Ives problem is one of deduction and reasoning. The centuries-old original poem states:

While on my way to St. Ives,

I met a man with seven wives.

Each wife had seven sacks;

Each sack had seven cats;

Each cat had seven kits.

Kits, cats, sacks, wives;

How many were going to St. Ives?

The popular Rubik’s Cube puzzle requires a player to spin sections of the cube in order to make the colors on all six sides match.

By this time, most people start adding and multiplying, trying to come up with the answer. But in reality, it’s a trick question: The narrator is on the way to St. Ives; the group he or she met along the way were leaving, not going to, St. Ives. Therefore, the number “going to St. Ives” equals (at least) one: the narrator.

Of course, there are some mathematicians who can’t leave well enough alone, and have calculated the total number of cats, kits, sacks, and wives, based on a geometric series. According to this equation, 2,801 were going to St. Ives, if the man, his wives, their cats, etc. had turned around.