When you create arithmetic expressions that involve several operators, the order that the program evaluates the various elements of the expression becomes important. In general, the program evaluates expressions from left to right. However, it also follows the rules of precedence from basic math.
Example
Multiplication and division are performed first from left to right and then addition and subtraction are performed.
For example, 5 + 10 * 3 = 5 + 30 = 35. You can change this order of precedence by using parentheses. For example, (5 + 10) * 3 = 15 * 3 = 45. If you are unsure of the order of precedence, it is a good idea to clarify your intentions with parentheses.