6.RP.A.2
6th Grade
Ratios & Proportional Relationships
Unit Rate Concept
Understand the concept of a unit rate associated with a ratio, and use rate language in the context of a ratio relationship.
How to explain it
At this standard, students understand unit rate as a ratio with denominator 1, compute unit rates by dividing, and use rate language to describe unit rates in real-world contexts.
The anchor students hold onto: Divide the first quantity by the second — unit rate denominator is always 1.
Unit rate (6.RP.A.2) bridges directly to applying ratio reasoning in tables, graphs, and equations (6.RP.A.3).
Worked examples
Example 1
Unit Rate
$3.60 earned in 4 hours
Step 1Identify: $3.60 · 4 hours
Step 2Divide first ÷ second: $3.60 ÷ 4 = $0.90
Step 3Unit rate: $0.90 per hour
Step 4"The student earns $0.90 per hour."
Answer$0.90 per hour
Example 2
Speed
150 miles in 3 hours
Step 1Identify: 150 miles · 3 hours
Step 2Divide: 150 ÷ 3 = 50
Step 3Unit rate: 50 miles per hour
Step 4"The car travels 50 miles per hour."
Answer50 miles per hour
Common mistakes
What students write
Dividing second ÷ first instead of first ÷ second to find the unit rate.
The fix
Always divide first ÷ second. 120 miles in 3 hours → 120 ÷ 3 = 40 mph.
Try this
A student finds the unit rate for 120 miles in 3 hours by calculating 3 ÷ 120 = 0.025. Find the error and correct it. Student's Work: Divide: 3 ÷ 120 = 0.025 Unit rate: 0.025 miles per hour
What students write
Giving just a number without units — writing "40" instead of "40 miles per hour."
The fix
Always label the unit rate with its units. The units tell what each 1 of represents.
Teacher tip
Head off the two predictable errors before they happen. First: Always divide first ÷ second. 120 miles in 3 hours → 120 ÷ 3 = 40 mph. Second: Always label the unit rate with its units. The units tell what each 1 of represents.