30 minutes · Pair work · Calculator. All amounts are invented and cover the same period. No deposits, withdrawals, dividends, fees or currency changes are included.
1. Compare money and percentages
Subtract the start from the end. Divide the change by the starting value and multiply by 100. Rank the accounts by money first, then by percentage.
On screen, the table can scroll sideways.
| Account | Start (SEK) | End (SEK) | Change (SEK) | Change (%) |
|---|---|---|---|---|
| A | SEK 1,000 | SEK 1,120 | SEK 120 | +12 % |
| B | SEK 3,000 | SEK 3,240 | SEK 240 | +8 % |
| C | SEK 2,000 | SEK 1,840 | −SEK 160 | −8 % |
Money: B, A, C. Percentage: A, B, C. Check that students use the starting value as the base and name the measure used for each ranking.
2. Use the same starting amount
Let each account start at SEK 1,000. Keep its percentage change from task 1. Calculate the new ending values and explain why the ranking in money changes.
On screen, the table can scroll sideways.
| Account | New start | New end |
|---|---|---|
| A | SEK 1,000 | SEK 1,120 |
| B | SEK 1,000 | SEK 1,080 |
| C | SEK 1,000 | SEK 920 |
A now leads in both money and percentage. This experiment uses different amounts but preserves each account’s rate of change.
3. Follow two periods for account A
After its 12% rise, A falls by 12%. Which amount is the new base? Calculate the ending value and the total change from the original SEK 1,000.
1,120 × 0.88 = SEK 985.60. Change: −SEK 14.40. Total: −1.44%. The base for the fall is SEK 1,120.
4. Exit question
One account rises from SEK 500 to SEK 575; another from SEK 2,000 to SEK 2,200. Which gains more money and which gains more in percentage terms?
The second: SEK 200 and 10%. The first: SEK 75 and 15%. Look for the correct base, units and minus signs. Ranking these fictional results does not forecast a future outcome.