Operator precedence describes the order in which operations are performed in
an arithmetic expression. For example:
var x = 100 + 50 * 3;
Is the result the same as 150 * 3, or is it the same as 100 + 150? Is the addition or the multiplication done first? As in traditional school mathematics, the multiplication is done first. Multiplication (*) and division (/) have higher precedence than addition (+) and subtraction (-). So the value of x of this particular equation is 250.
And (as in school mathematics) the precedence can be changed by using parentheses. When using parentheses, the operations inside the parentheses are computed first:
var x = (100 + 50) * 3; (The value of x is 450)
When many operations have the same precedence (like addition and subtraction), they are computed from left to right:
var x = 100 + 50 - 3; (The value of x is 147)
