Here’s a proof for you. It won’t be satisfying, but it will be quick.

Math Professor: Pick a number bigger than 7.

Student: 43.

Math Professor: That’s too big. Pick another number.

Student: 27?

Math Professor: Oooh! I like 27!

I guess we can use t as our variable for this problem. *in an imitating voice* Look at me I’m a physics major, and I love to use time as a variable for everything!

Gauss discovered the pairwise addition trick to spite his teacher. And now we call him the Prince of Mathematicians. Sometimes being a little shit pays off.