Okay, so there was a man a long time ago named Pafnuty Chebyshev. He was really good at math and he figured out a lot of really important stuff that helps us do math today.
One of the things he's famous for is something called Chebyshev's inequality. This is a fancy way of saying that if you have a bunch of numbers and you want to know how spread out they are, you can use Chebyshev's inequality to figure it out.
Here's an example: let's say you have some test scores for a class. Some people did really well and some people did not so well. Chebyshev's inequality helps you figure out how spread out those scores are.
It's kind of like if you have a big pile of candy and you want to know if everyone in the room can have some. Chebyshev's inequality can tell you how many candies each person can have and still make sure there's enough for everyone.
Basically, Chebyshev was a really smart guy who helped us understand how numbers work and how to use them to solve problems.