You use your mouse to click the numbers and then either add, subtract, divide, multiply, square, or put an exponent on them. This is a process called 'Math' in America, where you place numbers together and figure out an answer to them. If you don't have a mouse, use your mousepad or keyboard to figure it out. ~(o-o)~ Sadly, if you still don't understand, I have no other way of explaining a calculator to you.
