Primary 6 PSLE Mathematics Multiplication Division Quiz

Primary 6 PSLE Mathematics Quiz - Multiplication Division (Answer Key)

Total Marks: 50

Section A: Multiple-Choice Questions (5 × 1 mark = 5 marks)

1. Answer: (2) 5508
Working:
324 × 17 = 324 × (10 + 7) = 3240 + 2268 = 5508
Marking: 1 mark for correct answer.
Explanation for new students: Break 17 into 10 and 7. Multiply 324 by 10 (add a zero → 3240). Multiply 324 by 7 (300×7=2100, 20×7=140, 4×7=28 → 2268). Add them: 3240 + 2268 = 5508.

2. Answer: (2) 80
Working:
4800 ÷ 60 = 4800 ÷ 10 ÷ 6 = 480 ÷ 6 = 80
Marking: 1 mark for correct answer.
Explanation for new students: Dividing by 60 is the same as dividing by 10 first (remove one zero → 480), then dividing by 6. 480 ÷ 6 = 80.

3. Answer: (1) 25 × 50 − 25 × 2
Working:
25 × 48 = 25 × (50 − 2) = 25 × 50 − 25 × 2
Marking: 1 mark for correct answer.
Explanation for new students: 48 is 2 less than 50. So 25 × 48 = 25 × (50 − 2). By the distributive property, this equals 25×50 − 25×2. Option (3) also works (20+5=25), but (1) is the intended split using 50 and 2.

4. Answer: (2) 4320
Working:
Biscuits per box = 24 × 12 = 288
Biscuits in 15 boxes = 288 × 15 = 4320
Marking: 1 mark for correct answer.
Explanation for new students: First find biscuits in one box: 24 packets × 12 biscuits = 288. Then multiply by 15 boxes: 288 × 15 = 288 × 10 + 288 × 5 = 2880 + 1440 = 4320.

5. Answer: (1) 2
Working:
375 × 16 = 375 × 8 × 2 (since 16 = 8 × 2)
Marking: 1 mark for correct answer.
Explanation for new students: 16 can be split into 8 × 2. So 375 × 16 = 375 × (8 × 2) = 375 × 8 × 2.

Section B: Short-Answer Questions (5 × 2 marks = 10 marks)

6. Answer: (3) 4417
Working:
Number = (Divisor × Quotient) + Remainder = (18 × 245) + 7 = 4410 + 7 = 4417
Marking: 1 mark for correct method (using formula), 1 mark for correct answer.
Explanation for new students: The formula is: Dividend = (Divisor × Quotient) + Remainder. Here, Divisor = 18, Quotient = 245, Remainder = 7. So Number = (18 × 245) + 7. 18 × 245 = 18 × 200 + 18 × 45 = 3600 + 810 = 4410. Add 7 → 4417.

7. Answer: (1) 10
Working:
7200 ÷ 90 = 7200 ÷ (9 × 10) = 7200 ÷ 9 ÷ 10
Marking: 1 mark for correct method (factorising 90), 1 mark for correct answer.
Explanation for new students: 90 = 9 × 10. Dividing by 90 is the same as dividing by 9 then by 10. So the blank is 10.

8. Answer: (1) 8760
Working:
365 × 24 = 365 × 20 + 365 × 4 = 7300 + 1460 = 8760
Marking: 1 mark for correct method (splitting 24), 1 mark for correct answer.
Explanation for new students: 24 years = 24 × 365 days. Split 24 into 20 + 4. 365 × 20 = 7300. 365 × 4 = 1460. Total = 8760.

9. Answer: (1) 10185
Working:
3 weeks = 21 days
485 × 21 = 485 × 20 + 485 = 9700 + 485 = 10185
Marking: 1 mark for converting weeks to days, 1 mark for correct multiplication and answer.
Explanation for new students: 1 week = 7 days, so 3 weeks = 21 days. Multiply daily production (485) by 21: 485 × 20 = 9700, plus one more 485 = 10185.

10. Answer: (4) 3800 ÷ 70
Working:
5600 ÷ 80 = 70 (no remainder)
7200 ÷ 90 = 80 (no remainder)
4500 ÷ 60 = 75 (no remainder)
3800 ÷ 70 = 54 remainder 20
Marking: 1 mark for checking each option, 1 mark for correct answer.
Explanation for new students: Check each division. 5600÷80=70 exactly. 7200÷90=80 exactly. 4500÷60=75 exactly. 3800÷70: 70×50=3500, remainder 300; 70×4=280, remainder 20. So it has a remainder.

Section C: Short-Answer Questions (5 × 2 marks = 10 marks)

11. Answer: 12208
Working:
436 × 28 = 436 × (20 + 8) = 8720 + 3488 = 12208
Marking: 1 mark for correct method (e.g., long multiplication or splitting), 1 mark for correct answer.
Explanation for new students: Split 28 into 20 + 8. 436 × 20 = 8720. 436 × 8 = 3488 (400×8=3200, 30×8=240, 6×8=48). Add: 8720 + 3488 = 12208.

12. Answer: 216
Working:
5832 ÷ 27
27 × 200 = 5400, remainder 432
27 × 16 = 432
So 5832 ÷ 27 = 216
Marking: 1 mark for correct method (long division), 1 mark for correct answer.
Explanation for new students: Use long division. 27 goes into 58 twice (54), remainder 4. Bring down 3 → 43. 27 goes into 43 once (27), remainder 16. Bring down 2 → 162. 27 goes into 162 six times (162). Answer: 216.

13. Answer: 18 days
Working:
324 ÷ 18 = 18
Marking: 1 mark for correct division, 1 mark for correct answer with unit.
Explanation for new students: Total pages ÷ pages per day = number of days. 324 ÷ 18. 18 × 10 = 180, 18 × 8 = 144, 180+144=324. So 18 days.

14. Answer: 144 packets
Working:
Total pencils = 48 × 36 = 1728
Number of packets = 1728 ÷ 12 = 144
Marking: 1 mark for finding total pencils, 1 mark for correct final answer.
Explanation for new students: First find total pencils: 48 boxes × 36 pencils = 1728. Then divide by 12 pencils per packet: 1728 ÷ 12 = 144 packets.

15. Answer: 12
Working:
8400 ÷ 70 = 120
120 = 12 × 10
Marking: 1 mark for correct division, 1 mark for correct answer.
Explanation for new students: 8400 ÷ 70 = 840 ÷ 7 = 120. The question asks for the number that when multiplied by 10 gives 120. That number is 12.

Section D: Structured / Long-Answer Questions (5 × 5 marks = 25 marks)

16. Answer: 825 chairs
Working:
Total chairs = 25 × 38 = 950
Chairs left = 950 − 125 = 825
Marking: 1 mark for finding total chairs (25×38), 1 mark for correct subtraction, 1 mark for correct final answer, 2 marks for clear working presentation.
Explanation for new students: First calculate total chairs: 25 rows × 38 chairs = 950 chairs. Then subtract the 125 removed chairs: 950 − 125 = 825 chairs left.

17. Answer: 144
Working:
Other number = 6480 ÷ 45 = 144
Marking: 1 mark for setting up division, 1 mark for correct division method, 1 mark for correct answer, 2 marks for clear working presentation.
Explanation for new students: Product = Number 1 × Number 2. So Number 2 = Product ÷ Number 1 = 6480 ÷ 45. 45 × 100 = 4500, remainder 1980. 45 × 40 = 1800, remainder 180. 45 × 4 = 180. Total = 100+40+4 = 144.

18. Answer: 660 bags
Working:
Apples per basket = 5280 ÷ 44 = 120
Bags per basket = 120 ÷ 8 = 15
Total bags = 15 × 44 = 660
Alternative: Total bags = 5280 ÷ 8 = 660
Marking: 1 mark for correct method (either approach), 1 mark for apples per basket, 1 mark for bags per basket, 1 mark for total bags, 1 mark for correct final answer.
Explanation for new students: Method 1: Find apples per basket (5280 ÷ 44 = 120). Then bags per basket (120 ÷ 8 = 15). Total bags = 15 × 44 = 660. Method 2 (faster): Total bags = Total apples ÷ apples per bag = 5280 ÷ 8 = 660.

19. Answer: 18
Working:
25 × 18 × 4 = 25 × 4 × 18 (commutative property)
Marking: 1 mark for recognising rearrangement, 1 mark for correct answer, 3 marks for clear explanation of commutative property.
Explanation for new students: Multiplication can be done in any order (commutative property). The expression 25 × 18 × 4 is the same as 25 × 4 × 18. So the blank is 18.

20. Answer: 32400 pages
Working:
2 hours 15 minutes = 135 minutes
Pages = 240 × 135 = 240 × 100 + 240 × 35 = 24000 + 8400 = 32400
Marking: 1 mark for converting time to minutes, 1 mark for setting up multiplication, 1 mark for correct multiplication method, 1 mark for correct answer, 1 mark for clear working presentation.
Explanation for new students: Convert 2 hours 15 minutes to minutes: 2 × 60 + 15 = 135 minutes. Multiply pages per minute (240) by 135: 240 × 135 = 240 × 100 + 240 × 30 + 240 × 5 = 24000 + 7200 + 1200 = 32400.

End of Answer Key