PEMDAS is an acronym for the order in which mathematical operations should be performed as you move from left to right through an expression or equation:

You may have had PEMDAS introduced to you as “Please Excuse My Dear Aunt Sally.” Excuse us, but that’s a supremely lame 1950s-style acronym. We prefer, Picking Eminem Made Dre A Star. Whatever. Just remember PEMDAS.

If an equation contains any or all of these PEDMAS elements, first carry out the math within the parentheses, then work out the exponents, then the multiplication, and the division. Addition and subtraction are actually a bit more complicated. When you have an equation to the point that it only contains addition and subtraction, perform each operation moving from left to right across the equation.

An example will make this easier to get:

First work out the math in the parentheses (following PEMDAS even within the parentheses—always do multiplication before subtraction):

Now work out the exponents:

Then do the multiplication:

Then the division:

Leaving you with just addition and subtraction. Now work from left to right:

And finally: