Codes: AC9M7N06, AC9M7N09. Goal: calculate simple percentages of a quantity using efficient decomposition and interpret the unit. Prepare: 100-grid/benchmark strip.
- Question · 2 min. “A fictional 80-minute playlist is 25% complete. How many minutes have played?” Ask what 100% represents.
- Model · 5 min.
25% = 1/4; one quarter of 80 is 20 minutes. Show 4 equal bars of 20 and check 4 × 20 = 80. - Guided second path · 6 min. Find 15% of 60: 10% is 6, 5% is 3, total 9. Say 15% means 15 per 100 of the whole, even though we calculate with useful parts.
- Choice practice · 7 min. Pairs choose 20% of 45 (9) for a fictional poster space, or 12.5% of 48 (6) for a fictional game progress bar. They state the whole, unit, method and reasonableness check. The context does not alter the arithmetic.
- Spot a mismatch · 3 min. Display
25% of 80 = 25. Ask why copying the percent number ignores the whole. Rebuild one quarter. - Exit · 2 min. Everyone finds 30% of 50 → 15, via 10% × 3 or 3/10. Focus learners explain the unit.
Access: tactile segmented bar, enlarged text, calculator after a model if individual plan allows; avoid speed-only judgement.