The generally accepted convention for order of operations is to do all operations within parenthesis first followed by exponential notation, multplication then division (lefttoright), and addition and subtraction from lefttoright.
The acronym PEMDAS (Please Excuse My Dear Aunt Sally) was designed to help students remember this conventional 'order'as they simplified expressions: parenthesis  exponents  multiplication  division  addition  subtraction.
A similar acronym, BEMDAS (Brackets Exponents Multiplication Division Addition Subtraction) is the same thing but with the B exchanged for the P for parenthesis.
An acronym that I prefer is GEMA (Grouping Exponents Multiplication Addition). Now, why did I not include division and subtraction in my acronym? It's simple~we are always using the inverse of these operations when simplifying expressions in prealgebra so it is a 'given,' as far as I am concerned so why nitpick over a letter or two? You should have this ingrained by now and the acronym is simply to help remind you that order matters.
