What do the letters on a calculator mean?

Answer 1

I assume you mean graphing calculators. They are variables that you can store numbers to, like if you need to use it later on in a math problem. But they can't be used to figure out algebra equations. Say you have the equation n+1=2 and n+m=4. You would figure out the value of n, which is 1, and you could either remember it or store it to variable n. Then you could use the variable n in figuring out m instead of putting in 1. (4-n=m instead of 4-1=m)