Primary 4 Mathematics Multiplication Division Quiz

Primary 4 Mathematics Quiz - Multiplication Division (Answer Key)

Total Marks: 40

Section A: Multiple-Choice Questions (10 × 1 mark = 10 marks)

1. Answer: (2) 1944
Working: 324 × 6 = (300 × 6) + (20 × 6) + (4 × 6) = 1800 + 120 + 24 = 1944
Concept: Multiplication of a 3-digit number by a 1-digit number using place value partitioning.

2. Answer: (2) 4500 ÷ 90
Working: 4500 ÷ 9 = 500. 4500 ÷ 90 = 50. 450 ÷ 9 = 50. Both give 50.
Concept: Division by multiples of 10 — dividing both dividend and divisor by 10 gives the same quotient.

3. Answer: (2) 54
Working: 27 × 8 = 216. 216 ÷ 4 = 54. Alternatively: 27 × 8 = 27 × (4 × 2) = (27 × 2) × 4 = 54 × 4.
Concept: Using the associative property of multiplication to find a missing factor.

4. Answer: (2) 1018
Working: Number = (Divisor × Quotient) + Remainder = (7 × 145) + 3 = 1015 + 3 = 1018.
Concept: Division algorithm: Dividend = Divisor × Quotient + Remainder.

5. Answer: (2) 32
Working: Total pencils = 8 × 24 = 192. Pencils per packet = 192 ÷ 6 = 32.
Concept: Two-step word problem involving multiplication then division.

6. Answer: (2) 70
Working: 5600 ÷ 80 = 560 ÷ 8 = 70. (Cancel one zero from both numbers)
Concept: Division by tens — cancel common zeros in dividend and divisor.

7. Answer: (2) 270
Working: Other number = 2160 ÷ 8 = 270.
Concept: Finding a missing factor given the product and one factor.

8. Answer: (2) 5
Working: 43 × 25 = 43 × (20 + 5) = 43 × 20 + 43 × 5. The missing number is 5.
Concept: Distributive property of multiplication over addition.

9. Answer: (1) 2695
Working: 385 × 7 = (300 × 7) + (80 × 7) + (5 × 7) = 2100 + 560 + 35 = 2695.
Concept: Multiplication of a 3-digit number by a 1-digit number in a real-world context.

10. Answer: (2) 80
Working: 7200 ÷ 90 = 80. Check: 90 × 80 = 7200.
Concept: Finding a missing divisor using inverse operation (multiplication).

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

11. Answer: 3663 [2]
Working:
407 × 9 = (400 × 9) + (0 × 9) + (7 × 9) = 3600 + 0 + 63 = 3663
Marking: 1 mark for correct method (partitioning or vertical multiplication), 1 mark for correct answer.
Common mistake: Forgetting the zero in the tens place (writing 363 instead of 3663).

12. Answer: 972 [2]
Working:
5832 ÷ 6
6 ) 5832
-48 (6 × 8 = 48)
103
- 6 (6 × 1 = 6)
432
-42 (6 × 7 = 42)
12
-12 (6 × 2 = 12)
0
Answer: 972
Marking: 1 mark for correct long division steps, 1 mark for correct answer.
Alternative: 5832 ÷ 6 = (5400 ÷ 6) + (420 ÷ 6) + (12 ÷ 6) = 900 + 70 + 2 = 972.

13. Answer: 2940 [2]
Working:
245 × 12 = 245 × (10 + 2) = (245 × 10) + (245 × 2) = 2450 + 490 = 2940
Marking: 1 mark for correct method (distributive property or vertical multiplication), 1 mark for correct answer.
Common mistake: 245 × 12 = 245 × 10 + 2 = 2452 (forgetting to multiply 245 by 2).

14. Answer: 54 [2]
Working: 486 ÷ 9 = 54
Check: 54 × 9 = 486
Marking: 1 mark for correct division method, 1 mark for correct answer.
Concept: Division as equal sharing/grouping in a word problem context.

15. Answer: 3.6 [2]
Working: Each term is divided by 10 to get the next term.
3600 ÷ 10 = 360
360 ÷ 10 = 36
36 ÷ 10 = 3.6
3.6 ÷ 10 = 0.36
Marking: 1 mark for identifying the pattern (÷10), 1 mark for correct answer.
Concept: Number patterns involving multiplication/division by powers of 10, extending to decimals.

Section C: Structured / Long Answer Questions (5 × 4 marks = 20 marks)

16. (a) Answer: 1080 [2]
Working: 8 × 135 = 1080
Marking: 1 mark for correct multiplication (8 × 135), 1 mark for correct answer.

(b) Answer: 840 [2]
Working: 1080 − 240 = 840
Marking: 1 mark for correct subtraction using answer from (a), 1 mark for correct answer.
Note: If (a) is wrong but (b) correctly uses the wrong answer from (a), award 1 mark for (b) (follow-through).

17. (a) Answer: 432 m² [2]
Working: Area = Length × Breadth = 24 × 18 = 432 m²
Marking: 1 mark for correct formula (L × B), 1 mark for correct calculation and unit.

(b) Answer: 48 [2]
Working: Area of 1 tile = 3 × 3 = 9 m². Number of tiles = 432 ÷ 9 = 48.
Alternative: Along length: 24 ÷ 3 = 8 tiles. Along breadth: 18 ÷ 3 = 6 tiles. Total = 8 × 6 = 48.
Marking: 1 mark for correct method (area of tile ÷ total area OR tiles along each side), 1 mark for correct answer.
Common mistake: Forgetting to find area of tile first (doing 432 ÷ 3 = 144).

18. (a) Answer: 54 [2]
Working: 432 ÷ 8 = 54 boxes
Marking: 1 mark for correct division, 1 mark for correct answer.

(b) **Answer: $324** [2] **Working:** 54 ×$6 = $324
Marking: 1 mark for correct multiplication using answer from (a), 1 mark for correct answer with dollar sign.
Note: Follow-through applies if (a) is incorrect but (b) correctly multiplies by 6.

19. Answer: 1470 pages [4]
Working:
Rate per minute = 245 ÷ 5 = 49 pages/min
Pages in 30 minutes = 49 × 30 = 1470 pages
Alternative: 30 minutes = 6 × 5 minutes. Pages = 245 × 6 = 1470 pages.
Marking:

• 1 mark for finding rate (245 ÷ 5 = 49) OR recognising 30 min = 6 × 5 min
• 1 mark for correct multiplication (49 × 30 or 245 × 6)
• 1 mark for correct calculation
• 1 mark for correct final answer with unit
  Concept: Rate problems — find unit rate then multiply, or use proportional reasoning.

20. Answer: 8 mice [4]
Working:
Cost of 6 laptops = 6 × $785 =$4710
Total spent = $5000 −$150 = $4850 Money spent on mice =$4850 − $4710 =$140
Number of mice = $140 ÷$25 = 5.6 → Not a whole number!
Wait — let me recalculate:
6 × 785 = 4710
5000 − 150 = 4850
4850 − 4710 = 140
140 ÷ 25 = 5.6

Correction: The numbers need to give a whole number. Let me adjust the question numbers in the answer key to match a valid version.
Actually, for the answer key, I'll use the intended numbers that work:
If laptops cost $785 each: 6 × 785 = 4710. 5000 − 150 = 4850. 4850 − 4710 = 140. 140 ÷ 25 = 5.6 ✗

Let me use a corrected version that works:
Suppose laptops are $775 each: 6 × 775 = 4650. 5000 − 150 = 4850. 4850 − 4650 = 200. 200 ÷ 25 = 8 ✓

For this answer key, I'll provide the working for the corrected valid numbers:
**Working (with corrected laptop price $775):** Cost of 6 laptops = 6 ×$775 = $4650 Total spent =$5000 − $150 =$4850
Money spent on mice = $4850 −$4650 = $200 Number of mice =$200 ÷ $25 = 8

Marking:

• 1 mark for finding cost of laptops (6 × price)
• 1 mark for finding total spent (5000 − 150)
• 1 mark for finding money spent on mice (subtraction)
• 1 mark for dividing by 25 to get number of mice (must be whole number)

Note to teacher: The question as printed has a typo (laptop price should be $775, not$785, to give a whole number answer). Please adjust accordingly when administering.

End of Answer Key