PEMDAS!!
or an easy way to remember it is Please Excuse My Dear Aunt Sally
which stands for Parentheses, Exponent, Multiplication, Division, Addition, and Subtraction Go in order from p to s from left to right as you would read it
Parentheses first (9-3^2) start with the exponent 3^2=9 then subtract
(9-9)=0 so now we have 2+6(0)-2 Multiply next so 6(0)=0 then we have 2+0-2
next add 2+0=2 then we have 2-2 then subtract 2-2=0 so the overall answer is 0
but you have multiply, added, and subtracted throughout the process
