Sixth Grade · Math · week 3

Unit rates: the best buy

Compute a unit rate from a ratio and use unit rates to compare prices and speeds.

A unit rate compares an amount to exactly ONE of something - dollars per 1 item, or miles per 1 hour. To find a unit rate, divide the first number by the second.

Unit rates let you compare deals that come in different-sized packages. If 4 granola bars cost $2, the unit rate is $2 ÷ 4 = $0.50 per bar.

To find the best buy, find the unit price for each option and compare - the smaller unit price is the better deal, assuming the same quality.

📋 For the teacher
Teach it (10–15 min):
  • Always ask "per ONE what?" - per 1 item, per 1 hour, per 1 dollar - naming the unit keeps the division straight.
  • Divide the total by the number of units to get "how much for one."
  • Line up two unit rates side by side before deciding which is the better deal.
  • Use real receipts or a store app to compare unit prices together.
Talk about it:
  • What does "unit rate" mean in your own words?
  • Why is it fair to compare unit rates even when the packages are different sizes?
  • Where have you seen a "price per ounce" label at a store?

Mastery looks like: They compute a unit rate by dividing and use unit rates to correctly identify the better buy between two options.

Common stumbles: Dividing in the wrong order (dividing the smaller number by the larger); comparing totals instead of unit rates.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Math for this learner.
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