What tells you which operation to preform first?

The order of operations, often remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction), dictates which operations to perform first in a mathematical expression. This hierarchy ensures that calculations are executed in a consistent manner to achieve accurate results. Parentheses take the highest priority, followed by exponents, then multiplication and division from left to right, and finally addition and subtraction from left to right.