Understand the idea.
Join the costs
To buy two items, you must pay both prices. Add the costs to find the total. A three-dollar pencil and a four-dollar ruler cost dollars. The answer counts dollars, not the number of items.
Change is money returned
Change is the part of your payment returned after the cost is taken out. Count up from the cost to the amount paid, or subtract. Check that the cost and the change together make exactly the payment.
See the method in action.
Buy two items
A bookmark costs 2 dollars and a pen costs 5 dollars. How much do they cost together?
Worked solution
- 1
Collect both prices.
The bookmark costs two dollars and the pen costs five dollars; both must be paid.
- 2
Join the costs.
Adding the two prices finds the total cost.
- 3
State the money amount.
The total is seven dollars for the two items together.
7 dollars.
Find the change
A puzzle costs 8 dollars. Mia pays with a 10-dollar note. What change should she get?
Worked solution
- 1
Take the cost out of the payment.
Mia pays ten dollars, but only eight dollars is needed for the puzzle.
- 2
Check the change against the payment.
The eight-dollar cost and two-dollar change use the whole ten-dollar payment.
- 3
Return the unused money.
The two dollars left over is the change Mia should receive.
2 dollars change.
Try it yourself.
Check your understanding
You buy a 4-dollar item and pay 5 dollars. What change do you get?
Show answer & reasoning
1 dollar.
Take the four-dollar cost from the five-dollar payment: . Check , so the change is one dollar.
Keep practising
6 worksheet questions
Read the questions online
- A card costs 3 dollars and a sticker sheet costs 2 dollars. Find the total cost.
- Two postcards cost 2 dollars each. Find their total cost.
- An item costs 6 dollars. You pay 10 dollars. Find the change.
- A bag costs 9 dollars. Can you pay exactly with four 2-dollar coins and one 1-dollar coin?
- A pen costs 3 dollars and a pad costs 5 dollars. You have 7 dollars. How much more is needed?
- A game costs 7 dollars. You pay 10 dollars and receive 2 dollars change. Is the change correct? Explain.
Read the worked solutions
- A card costs 3 dollars and a sticker sheet costs 2 dollars. Find the total cost.
.
5 dollars. - Two postcards cost 2 dollars each. Find their total cost.
.
4 dollars. - An item costs 6 dollars. You pay 10 dollars. Find the change.
.
4 dollars. - A bag costs 9 dollars. Can you pay exactly with four 2-dollar coins and one 1-dollar coin?
.
Yes. - A pen costs 3 dollars and a pad costs 5 dollars. You have 7 dollars. How much more is needed?
The total cost is 8 dollars; .
1 dollar. - A game costs 7 dollars. You pay 10 dollars and receive 2 dollars change. Is the change correct? Explain.
, not 10. The correct check is .
No. It should be 3 dollars change.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Comparing prices; $1/$2 coins and notes; purchases; limited money and saving; needs/wants; consumer choices.
Official curriculum source ↗