If I do var a=3 and var b=4 and then do var c=a+b it tells me the answer is 34. Why?

The plus (+) is an operator that can be used for strings (e.g. letters) as well as numbers. The operator will first assume you want var a and var b work as letters not number. That means it just attaches them to 34. To make a mathematical equation out of it you have to tell the program that var a and var b are numbers by doing int(a) and int(b) while int stand for "integer".