Average
The most common mistakes Singapore primary students make in Average, distilled from 74+ MOE-aligned questions across P5, P6. Free practice at every level.
Top 10 mistakes in Average
- #1Misconception
This is the total, not the average.
- #2Misconception
Confused the new average (20 kg) with the answer to the question.
- #3Misconception
Confused the original average (24 kg) with the heaviest box itself.
- #4Partial logic
Computed the total mass of the remaining 5 boxes (5 × 20 = 100 kg) and gave that as the heaviest box mass, confusing total with a single value.
- #5Calc error
Divided total by 5 instead of 4 days.
- #6Misconception
This comes from subtracting the two averages: 84 − 80 = 4. You cannot subtract averages directly. Find the total for each group: original total = 5 × 84 = 420, new total = 6 × 80 = 480, sixth number = 480 − 420 = 60.
- #7Calc error
This uses 5 instead of 6 as the count for the new group: 84 × 5 − 80 × 5 = 420 − 400 = 20. After adding the sixth number there are 6 numbers, so the new total is 80 × 6 = 480.
- #8Calc error
This uses 6 instead of 5 as the count for the original group: 84 × 6 − 80 × 6 = 504 − 480 = 24. The original group had only 5 numbers, so the correct original total is 84 × 5 = 420.
- #9Misconception
Assumed each of the 3 new boys must weigh the new average 44 kg.
- #10Calc error
Used the increase of 4 kg in average multiplied by 9 boys = 36 kg, then divided by 3 = 12 kg, then added to 36 to get 48 kg.
Practise Average by level
- Primary 542 questions
- Primary 632 questions
Practise every Average question — plus 75,000+ across all PSLE topics — with full worked solutions and misconception-specific feedback on Superholic Lab.
Start Free Trial — 7 Days FreeBrowse all PSLE topics →