If you have roommates, you’ve probably had to deal with how to split rent.

I care a lot about natural light, but not everyone does.

Is it worth not having a closet?

Or one might care more about the shape of the room, or its proximity to the bathroom.

“Sperner’s Lemma” was discovered in 1928 by mathematician Emanuel Sperner.

In 1999, math professor Francis Su applied it to splitting rent.

So how do you apply it?

With each step, the hypothetical prices get closer, and the decisions are trickier.

Each roommate continues answering until there’s a fair division.

No one will want to swap his room and price for someone else’s," the article says.

Thankfully, they’ve made it easy to put Sperner’s Lemma into practice.

you’re able to use theirrent division calculatorfor your own roommate situation.

And, for more detail, check out their full post.

To Divide the Rent, Start With a Triangle| The New York Times

Screenshot from NyTimes.com.