P: Parenthesis first
E: Exponents next
MD: Multiplication and Division next
AS: Addition and Subtraction last
Notice that the M and D are grouped together, as are the A and S. This is because Multiplication and Division are at the same priority level, and should be done in left to right order. Likewise, Addition and Subtraction are at the same priority level, and should be done in left to right order.
Unfortunately, many teachers donât realize this, and teach that all multiplication is done before all division, and all addition is done before all subtraction. I was taught that way all through elementary school, and it wasnât until I hit Jr/Sr high that I found out that Multiplication and Division are at the same priority level, as are Addition and Subtraction