PE(MD)(AS) is a way to remember the order of operations in math:
P: Parentheses
E: Exponents
(MD): Multiplication and division, from left to right
(AS): Addition and subtraction, from left to right 
The order of operations is also known as PEMDAS, which stands for Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction. Another way to remember the order of operations is BODMAS, which stands for Brackets, Orders (Powers or Roots), Division or Multiplication, Adding or Subtracting.