Understand the idea.
Plan before spending
A budget connects money available with planned spending. Add all costs first, then subtract that total from the available money. The remainder shows what can be saved or used for another purpose.
If the costs exceed the money available, the plan needs changing. Reduce a quantity, choose another suitable item or wait. Do not include the same money in two different spending plans.
Connect today with a future goal
For a future goal, separate money already saved from money that will be saved later. Work out the amount kept each week after spending, then multiply it by the number of weeks.
Add the new savings to the starting amount and compare with the target price. A deadline is met only if the total is enough by that date. This assumes the weekly saving and price stay the same.
See the method in action.
Money left today
A club has 48 dollars. It will spend 19 dollars on paper and 12 dollars on glue. How much remains?
Worked solution
- 1
Combine the planned costs.
Both paper and glue must come from the club money.
- 2
Find the amount remaining.
Money remaining is the available amount less all planned costs.
- 3
Check the budget balances.
Spending and remaining money together should equal the starting amount.
17 dollars
Check a deadline
Noah has 18 dollars and saves 6 dollars a week. Will he have enough for a 50-dollar helmet after 5 weeks?
Worked solution
- 1
Calculate five weeks of saving.
Noah saves 6 dollars in each of the five weeks.
- 2
Include the money already saved.
The starting 18 dollars is separate from the new weekly savings.
- 3
Compare with the helmet price.
A positive shortfall means he cannot buy the helmet after five weeks.
- 4
Check what one more week would do.
A sixth equal saving would exceed 50 dollars if the price stays unchanged.
No. He will have 48 dollars, 2 dollars short.
Try it yourself.
Check your understanding
Receive 10 dollars each week and spend 3 dollars each week. How much can you save in 4 weeks?
Show answer & reasoning
28 dollars
Each week, dollars can be kept. Four equal weekly savings total dollars.
Keep practising
6 worksheet questions · 14 marks
Read the questions online
- You have 35 dollars and spend 14 dollars. How much remains?2 marks
- A class has 60 dollars and plans costs of 24 and 18 dollars. Find the amount left.2 marks
- Save 5 dollars each week for 7 weeks. How much is saved?2 marks
- You have 12 dollars and save 4 dollars a week. Find the total after 6 weeks.2 marks
- Receive 9 dollars weekly and spend 2 dollars weekly. Starting with no savings, can you buy a 30-dollar book after 4 weeks?3 marks
- Buy one 2-dollar fruit cup for each of 8 people and one shared 6-dollar cracker bag. Is a 25-dollar budget enough, and what remains?3 marks
Read the worked solutions
Equivalent correct methods earn the corresponding marks. Include units where asked.
- You have 35 dollars and spend 14 dollars. How much remains?2 marks
.
21 dollars - A class has 60 dollars and plans costs of 24 and 18 dollars. Find the amount left.2 marks
Costs: .
.
18 dollars - Save 5 dollars each week for 7 weeks. How much is saved?2 marks
.
35 dollars - You have 12 dollars and save 4 dollars a week. Find the total after 6 weeks.2 marks
New savings: .
Total: .
36 dollars - Receive 9 dollars weekly and spend 2 dollars weekly. Starting with no savings, can you buy a 30-dollar book after 4 weeks?3 marks
Weekly saving: .
Four weeks: .
.
No; you will have 28 dollars, 2 dollars short. - Buy one 2-dollar fruit cup for each of 8 people and one shared 6-dollar cracker bag. Is a 25-dollar budget enough, and what remains?3 marks
Fruit: .
Cost: .
Left: .
Yes. The cost is 22 dollars and 3 dollars remains.
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics 2026
Practical models; immediate/future financial plans; consumer goals; ethical/sustainable choices.
Official curriculum source ↗