Algebra 1 / Unit 1: Expressions and Real Numbers
1.2 Order of Operations
Notes
Use PEMDAS to simplify in the right order: 1. Parentheses and other grouping symbols (brackets, fraction bars, absolute value) 2. Exponents 3. Multiplication and Division, left to right 4. Addition and Subtraction, left to right
- Multiplication does not always come before division. Work left to right: $12 \div 3 \cdot 2 = 4 \cdot 2 = 8$.
- Watch negatives with exponents: $-3^2 = -9$ but $(-3)^2 = 9$.
Practice
Simplify $8 + 2 \cdot 5^2$.
Exponent first: $5^2 = 25$. Then $2 \cdot 25 = 50$. Then $8 + 50 = 58$.
Simplify $24 \div 4 \cdot 3$.
Left to right: $24 \div 4 = 6$, then $6 \cdot 3 = 18$.
What is $-4^2$?
The exponent applies only to 4, then the negative: $-(4^2) = -16$.
Ready for more? Take the Unit 1 test.