The operator precedence rules for expression evaluation define the order in which adjacent (separated by at most one operand) operator of different precedence levels are evaluated.

Standard precedence level: Parenthesis Unary operators ** (if the language supports it) / + -

The operator associativity rules for expression evaluation define the order in which adjacent operators with the same precedence level are evaluated.

Standard associativity rules:

Left to right, except **, which is right to left. Precedence and associativity rules can be overridden by parenthesis.