When more than one operator appears in an expression, the order of evaluation depends on the rules of precedence. For mathematical operators, Python follows mathematical convention. The acronym PEMDAS is a useful way to remember the rules:
Parentheses have the highest precedence and can be used to force an expression to evaluate in the order you want. Since expressions in parentheses are evaluated first, 2 * (3 - 1) is 4, and (1 + 1) ** (5 - 2) is 8. You can also use parentheses to make an expression easier to read, as in (minute * 100) / 60, even if it doesn’t change the result.
Multiplication and Division have the same precedence, which is higher than Addition and Subtraction, which also have the same precedence. So 2 * 3 - 1 is 5, not 4, and 6 + 4 / 2 is 8, not 5.
Operators with the same precedence are evaluated from left to right. So the expression 5 - 3 - 1 is 1, not 3, because the 5 - 3 happens first and then 1 is subtracted from 2.
