SME
Grade 6 Math · Problem type
Compare unit prices
Use this for “Which is the better buy?”: compare the price of one item.
Diagram
One item: $1.25 at the first store, $1.15 at the second.
This is an example. Type your own values to start a new problem.
$
a
÷
m
=
$
p
$
b
÷
n
=
$
r
Difference for one item
worked out (not typed) · $
Formulas
5 ÷ 4 = 1.25
First store’s price ÷ items = price for one
6.9 ÷ 6 = 1.15
Second store’s price ÷ items = price for one
1.25 and 1.15 are 0.1 apart
Higher price for one − lower price for one = difference for one item
Assumptions
•
The better buy is the one with the lower price for one item.
•
The two stores sell the same item.
•
Prices are in dollars and cents; counts are whole numbers to 100.
Step-by-step
WE KNOW
First store’s total price: $5
Items at the first store: 4
Second store’s total price: $6.90
Items at the second store: 6
FIND
first store’s price for one, second store’s price for one, difference for one item
Step 1 · Find first store’s price for one
5 ÷ 4 = ?
First store’s price ÷ items = price for one
Find the price of one at the first store: divide.
1
.
2
5
4
)
5
.
0
0
−
4
1
0
−
8
2
0
−
2
0
0
First store’s price for one = $1.25
Step 2 · Find second store’s price for one
6.9 ÷ 6 = ?
Second store’s price ÷ items = price for one
Find the price of one at the second store: divide.
1
.
1
5
6
)
6
.
9
0
−
6
9
−
6
3
0
−
3
0
0
Second store’s price for one = $1.15
Step 3 · Find difference for one item
1.25 − 1.15 = ?
Higher price for one − lower price for one = difference for one item
Take the lower price for one from the higher one.
1
.
2
5
−
1
.
1
5
0
.
1
0
Difference for one item = $0.10 (the second store is the better buy)
Check
Put the numbers back in. Both sides should match.
1.25 × 4 = 5 ✓
1.15 × 6 = 6.9 ✓
1.25 − 1.15 = 0.1 ✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.