Order of Operations
Definition
The order of operations is a set of rules that defines the sequence in which mathematical operations should be performed. It ensures that everyone solving a mathematical expression will arrive at the same answer.
Prerequisites
To understand order of operations, you should have mastered:
Learning Objectives
After mastering order of operations, you should be able to:
- Remember the PEMDAS acronym and its meaning
- Apply operations in the correct order
- Evaluate expressions with multiple operations
- Use parentheses to group operations
- Solve problems with nested parentheses
- Identify common mistakes in order of operations
- Write expressions that evaluate to a given value
Key Concepts
PEMDAS Rule
- Parentheses
- Exponents
- Multiplication and Division (left to right)
- Addition and Subtraction (left to right)
Grouping Symbols
- Parentheses ( )
- Brackets [ ]
- Braces { }
- Nested grouping symbols
Special Cases
- Multiple sets of parentheses
- Multiple exponents
- Negative numbers
- Fractions in expressions
Examples
Example 1: Basic Order (Grade 5)
Problem: Evaluate 2 + 3 × 4
Solution: 1. Multiplication before addition 2. 3 × 4 = 12 3. 2 + 12 = 14 4. Answer: 14
Example 2: Parentheses (Grade 5)
Problem: Evaluate (2 + 3) × 4
Solution: 1. Parentheses first 2. 2 + 3 = 5 3. 5 × 4 = 20 4. Answer: 20
Example 3: Multiple Operations (Grade 6)
Problem: Evaluate 24 ÷ (3 + 5) - 2²
Solution: 1. Inside parentheses first: 3 + 5 = 8 2. Exponent: 2² = 4 3. Division: 24 ÷ 8 = 3 4. Subtraction: 3 - 4 = -1 5. Answer: -1
Common Misconceptions
- Always going left to right regardless of operation
- Doing multiplication after division always
- Not using parentheses when needed
- Forgetting to evaluate exponents before multiplication
Progression Path
This skill leads to:
Practice Activities
- Basic: Evaluate expressions with two operations
- Intermediate: Work with parentheses
- Advanced: Solve problems with multiple grouping symbols
- Challenge: Create expressions that evaluate to a target number