SME
Grade 6 Math · Ratios & Proportions
Unit rates
Use this for “6 muffins cost $7.50. How much does one muffin cost?”
Diagram
Number of items: 6 on the top line sits over $7.50 on the bottom line: each 1 above is $1.25 below.
This is an example. Type your own values to start a new problem.
$
c
×
n
=
$
t
Formulas
1.25 × 6 = 7.5
Cost per item × number of items = total cost
Assumptions
•
Every item costs the same: the rate stays the same.
•
The unit rate is the amount for 1.
•
Prices are in dollars and cents; counts are whole numbers to 1,000.
•
A price for one that isn’t a whole number of cents is shown to the cent: $10 for 3 is about $3.33 each.
Step-by-step
WE KNOW
Total cost: $7.50
Number of items: 6
FIND
cost per item
Step 1 · Find cost per item
? × 6 = 7.5
Cost per item × number of items = total cost
The unit rate is the price of 1. Share the total cost equally among the items.
Cost per item = 7.5 ÷ 6
1
.
2
5
6
)
7
.
5
0
−
6
1
5
−
1
2
3
0
−
3
0
0
Cost per item = $1.25
Check
Put the numbers back in. Both sides should match.
1.25 × 6 = 7.5 ✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.