My favorite math teacher often shouted "GEMAL says......!" What he means by that is to remember what this acronym means:
- Multiplication & Division
- Addition & Subtraction
- Left to Right
So, when performing the calculation remember to
- respect the parenthesis working from the inside out
- Solve the exponents if there are any, like changing 23 to 8 for example.
- Do multiplication/division before addition/subtraction
- Finally, do addition and subtraction last
- Within a given pair of parenthesis, do the above from left to right.
This explanation doesn't account for variable X but I thought to still share this as it has served me well over the years.