The order of operations ensures that everyone evaluates mathematical expressions the same way. Without agreed-upon rules, the expression 2 + 3 × 4 could equal either 20 or 14. The correct answer is 14, because multiplication comes before addition.

PEMDAS helps remember the order: Parentheses, Exponents, Multiplication/Division (left to right), Addition/Subtraction (left to right). Note that multiplication and division have equal priority, as do addition and subtraction — work left to right within each level.

Parentheses override the normal order. In (2 + 3) × 4, the parentheses tell us to add first, getting 5 × 4 = 20. Nested parentheses work from inside out. Understanding when and how to use parentheses gives students control over the order of calculations.

Mastering order of operations is essential for algebra, programming, and any field that uses formulas. Every spreadsheet formula, every line of code, and every mathematical equation depends on these rules being applied correctly and consistently.