Solve: 15 + 10 ÷ 5 × 2 - 3 Using Order of Operations

Mathematical operations have a specific hierarchy! Division and multiplication are stronger operations that must be done first. Working left to right would give you 25 ÷ 5 × 2 - 3 = 7, which is wrong.

Parentheses, Exponents, Multiplication and Division (left to right), Addition and Subtraction (left to right). Some people remember it as "Please Excuse My Dear Aunt Sally!"

Neither has priority over the other! When you have both multiplication and division, work from left to right. In this problem, division comes first, so we do $10 \div 5 = 2$ then $2 \times 2 = 4$.

Always substitute your answer back into a simplified version of the original problem. Here: $15 + 4 - 3$ should equal your final answer of 16.

Double-check your order of operations! The most common error is doing addition first. Remember:

• Step 1: $10 \div 5 = 2$
• Step 2: $2 \times 2 = 4$
• Step 3: $15 + 4 - 3 = 16$