Life skills · Grades 6–10
Budget arithmetic and opportunity cost
A simple budget compares available money with planned costs.
Understand the idea
Balance the amounts
A simple budget compares available money with planned costs.
Separate categories
One-off costs and recurring costs affect plans differently.
A choice excludes alternatives
Opportunity cost concerns the next-best option given up.
Worked examples
A fictional club has 120 units and spends 35 on materials and 28 on transport. How much remains?
120 − 35 − 28 = 57.
57
Which is a recurring cost in a monthly plan?
The fee repeats each month.
a monthly room fee
Try it yourself
Explain opportunity cost using a choice between two activities on the same afternoon.
A club saves 12 units each week for 7 weeks. Find the total saved.
A plan lists 90 units available and 105 units in costs. It has
- a 15-unit shortfall
- a 15-unit surplus
- no gap
- a 195-unit surplus
Why should an uncertain cost be included with an explicit estimate rather than ignored?
Answers and marking notes
Answers and marking notes
- Choosing one means giving up the next-best alternative that cannot be done at that time.
Credit the foregone alternative, not necessarily a money payment.
- 84
12 × 7 = 84.
- a 15-unit shortfall
Costs exceed available funds by 15.
- Ignoring it understates the likely total; an estimate and buffer make the uncertainty visible.
Credit transparent planning rather than false precision.
Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.