When typing numbers with a Mac, you may occasionally need to add exponents to your numbers. In typing, these are known as "superscript" characters. Apple includes a keyboard shortcut to use such characters. This avoids the hassle of going into "Special Characters" and selecting each number manually.
Move your cursor to where you want the exponent to appear.
Hold down the "Shift" and "Command" keys and hit the "+" key.
Type your exponent. It will appear raised in the proper position.
Repeat the key combination to return to regular format.
Not all Mac programs are superscript compatible. In this case, your only option is the write an exponent using the ^ key (such as 45^2).