ELI5: Explain Like I'm 5

Tannery's theorem

Okay kiddo, so imagine you have some numbers and you want to add them all up. But instead of adding them one by one, you can use something called Tannery's Theorem to make it easier.

Tannery's Theorem is like a shortcut for adding up all the numbers in a series. A series is just a fancy word for a bunch of numbers that come one after the other, like 1, 2, 3, 4, 5.

Here's how Tannery's Theorem works: you start by taking the first number in the series and adding it up. Then you take the second number in the series and subtract it. Then you take the third number and add it again, and the fourth number and subtract it, and so on and so on.

It might seem kind of confusing, but trust me it makes things easier in the end. By doing this over and over again, you can figure out what the sum of all the numbers in the series is without having to add them all up one by one.

So that's Tannery's Theorem for you, a helpful trick for adding up long series of numbers without getting too tired!