Calculating Unit Rates
The fastest way to calculate a unit rate in 6th grade is to divide the numerator by the denominator directly. For 384 dollars paid for 32 hours of work: 384 divided by 32 = 12 dollars per hour. For a car traveling 455 miles on 14 gallons: 455 divided by 14 = 32.5 miles per gallon. A printing plant producing 96,000 magazines in 12 hours makes 8,000 per hour. This direct division shortcut, from Reveal Math, Course 1, Module 1, gives 6th graders an efficient method for any unit rate problem.
Key Concepts
Once you understand the concept of scaling down to 1, you can use a direct calculation shortcut. To convert any rate to a unit rate , simply divide the numerator (the first quantity) by the denominator (the second quantity).
Common Questions
How do I calculate a unit rate?
Divide the first quantity (numerator) by the second quantity (denominator). This gives the amount per one unit of the second quantity.
What is a unit rate?
A unit rate is a ratio with a denominator of 1. It tells you how much of one quantity there is for every one unit of the other, like miles per hour or dollars per item.
A worker earns 280 dollars in 40 hours. What is the hourly rate?
Unit rate = 280 divided by 40 = 7 dollars per hour.
A car gets 390 miles on 15 gallons. What is the mpg?
Unit rate = 390 divided by 15 = 26 miles per gallon.
How is direct division for unit rates different from using a ratio table?
Both give the same answer, but direct division is faster. A ratio table is more visual and organized; direct division is a one-step calculation.
When do 6th graders learn direct division for unit rates?
Module 1 of Reveal Math, Course 1 covers calculating unit rates in the Ratios and Rates unit.