Primary 6 PSLE Mathematics Semestral Assessment 2 (End of Year) Paper 5

TuitionGoWhere Practice Paper — Mathematics Primary 6 PSLE

Answer Key — SA2 Practice Paper, Version 5 of 5

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Section A: Short Answer Questions (2 marks each)

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1. Write in numerals: Five million, three hundred and twelve thousand, six hundred and forty-eight.

Working:

• Five million = 5,000,000
• Three hundred and twelve thousand = 312,000
• Six hundred and forty-eight = 648
• Total = 5,000,000 + 312,000 + 648 = 5,312,648

Answer: 5,312,648 ✓

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2. Round 7,845,321 to the nearest hundred thousand.

Working:

• The hundred thousand digit is 8 (in 7,845,321 → the 8 is in the hundred thousands place: 7,800,000).
• The digit to the right (ten thousands place) is 4.
• Since 4 < 5, we round down.
• 7,845,321 → 7,800,000

Answer: 7,800,000 ✓

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3. Find the value of 4 × 250 × 50.

Working:

• Rearrange: 4 × 250 = 1,000
• 1,000 × 50 = 50,000

Answer: 50,000 ✓

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4. List all the factors of 72.

Working:

• 1 × 72 = 72
• 2 × 36 = 72
• 3 × 24 = 72
• 4 × 18 = 72
• 6 × 12 = 72
• 8 × 9 = 72

Answer: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72 ✓

Marking note: Award full marks if all 12 factors are listed. Deduct 1 mark if 1–2 factors are missing. Deduct 2 marks if more than 2 are missing or if non-factors are included.

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5. Find the LCM of 18 and 24.

Working:

• Prime factorisation:
  • 18 = 2 × 3²
  • 24 = 2³ × 3
• LCM = 2³ × 3² = 8 × 9 = 72

Answer: 72 ✓

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6. A factory produced 3,672 toys in January and 4,589 toys in February. Round the total to the nearest thousand.

Working:

• Total = 3,672 + 4,589 = 8,261
• Round 8,261 to nearest thousand: the hundreds digit is 2 (< 5), so round down.
• 8,000

Answer: 8,000 ✓

Marking note: Award 1 mark for correct addition and 1 mark for correct rounding.

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7. Find the value of 12,000 ÷ (15 × 8).

Working:

• 15 × 8 = 120
• 12,000 ÷ 120 = 100

Answer: 100 ✓

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8. 3,450,000 = 3 million + _________ thousands.

Working:

• 3 million = 3,000,000
• Remaining = 3,450,000 − 3,000,000 = 450,000
• 450,000 = 450 thousands

Answer: 450 ✓

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9. Arrange in order, starting with the smallest: 8,045,200 | 8,405,200 | 8,042,500 | 8,450,020

Working:

• Compare digit by digit from the left:
  • 8,042,500 (smallest — ten thousands digit is 4, thousands digit is 2)
  • 8,045,200 (ten thousands digit is 4, thousands digit is 5)
  • 8,405,200 (hundred thousands digit is 4)
  • 8,450,020 (hundred thousands digit is 4, ten thousands digit is 5 — largest)

Answer: 8,042,500; 8,045,200; 8,405,200; 8,450,020 ✓

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10. Which town has the greatest population?

Working:

• A: 2,345,678
• B: 2,435,678 ← hundred thousands digit is 4 (highest)
• C: 2,345,867
• D: 2,354,678

Comparing: B has 4 in the hundred thousands place, while A, C, D have 3.

Answer: Town B ✓

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Section B: Structured Short Answer Questions (4 marks each)

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11. A school library had 12,500 books. The school bought 3,750 new books in March and donated 2,180 old books in April.

(a) Books at end of April:

Working:

• After buying: 12,500 + 3,750 = 16,250
• After donating: 16,250 − 2,180 = 14,070

Answer (a): 14,070 books ✓

(b) Books per shelf (15 shelves):

Working:

• 14,070 ÷ 15 = 938

Answer (b): 938 books ✓

Marking note: Award 2 marks for (a) and 2 marks for (b). In (b), accept correct division even if (a) was wrong (error carried forward).

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12. HCF = 12, LCM = 360, one number = 60. Find the other number.

Working:

• Formula: HCF × LCM = Product of the two numbers
• 12 × 360 = 60 × (other number)
• 4,320 = 60 × (other number)
• Other number = 4,320 ÷ 60 = 72

Answer: 72 ✓

Marking note: Award 2 marks for correct formula application and 2 marks for correct answer. Accept alternative methods (e.g., prime factorisation).

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13. A fruit seller had 960 oranges. He packed them into bags of 12. Each bag sold for $5.

(a) Number of bags:

Working:

• 960 ÷ 12 = 80 bags

Answer (a): 80 bags ✓

(b) Total money collected:

Working:

• 80 × $5 = **$400**

Answer (b): $400 ✓

Marking note: Award 2 marks for (a) and 2 marks for (b). Error carried forward accepted in (b).

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14. Find 48 × 25 by rewriting 48 as (50 − 2).

Working:

• 48 × 25 = (50 − 2) × 25
• = 50 × 25 − 2 × 25
• = 1,250 − 50
• = 1,200

Answer: 1,200 ✓

Marking note: Award 2 marks for correct expansion and 2 marks for correct final answer.

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15. The number 5_3,826 is divisible by 9. Find the missing digit.

Working:

• Divisibility rule for 9: sum of all digits must be divisible by 9.
• Known digits: 5 + 3 + 8 + 2 + 6 = 24
• Let the missing digit be x.
• 24 + x must be divisible by 9.
• The next multiple of 9 after 24 is 27.
• x = 27 − 24 = 3

Answer: 3 ✓

Marking note: Award 2 marks for correct application of divisibility rule and 2 marks for correct answer.

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Section C: Word Problem Questions (4 marks each)

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16. Mr Tan earned $4,850 in January. In February, he earned$1,250 more than in January. In March, he earned twice as much as in February.

(a) February earnings:

Working:

• February = $4,850 +$1,250 = $6,100

Answer (a): $6,100 ✓

(b) March earnings:

Working:

• March = 2 × $6,100 = **$12,200**

Answer (b): $12,200 ✓

(c) Total earnings over three months:

Working:

• Total = $4,850 +$6,100 + $12,200 = **$23,150**

Answer (c): $23,150 ✓

Marking note: Award 1 mark for (a), 1 mark for (b), and 2 marks for (c). Error carried forward accepted throughout.

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17. A stadium seats 25,000 people. Football match: 18,450 occupied. Concert: full house.

(a) Empty seats during football match:

Working:

• 25,000 − 18,450 = 6,550

Answer (a): 6,550 seats ✓

(b) How many more people at the concert than the football match:

Working:

• Concert attendance = 25,000
• Difference = 25,000 − 18,450 = 6,550

Answer (b): 6,550 more people ✓

Marking note: Award 2 marks for (a) and 2 marks for (b). Error carried forward accepted in (b).

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18. Singapore population in 2020: 5,685,807. Increase in 2023: about 382,000. Round to nearest hundred thousand.

Working:

• 5,685,807 + 382,000 = 6,067,807
• Round to nearest hundred thousand: ten thousands digit is 6 (≥ 5), so round up.
• 6,067,807 → 6,100,000

Answer: 6,100,000 ✓

Marking note: Award 2 marks for correct addition and 2 marks for correct rounding.

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19. A machine produces 240 bottles/hour. Runs 8 hours/day, 6 days/week.

(a) Bottles per day:

Working:

• 240 × 8 = 1,920 bottles

Answer (a): 1,920 bottles ✓

(b) Bottles per week:

Working:

• 1,920 × 6 = 11,520 bottles

Answer (b): 11,520 bottles ✓

(c) Can the machine complete an order of 15,000 bottles in one week?

Working:

• Weekly production = 11,520 bottles
• 11,520 < 15,000
• No, the machine cannot complete the order in one week because it only produces 11,520 bottles, which is 3,480 bottles short.

Answer (c): No, because 11,520 < 15,000 (short by 3,480 bottles). ✓

Marking note: Award 1 mark for (a), 1 mark for (b), and 2 marks for (c) — 1 for correct conclusion (Yes/No) and 1 for valid explanation with supporting figures.

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20. Ali, Bala and Chris shared a sum of money. Ali received 2/5 of the total. Bala received 1/3 of the remaining money. Chris received $240.

(a) Fraction of total that Bala received:

Working:

• Ali received 2/5, so remaining = 1 − 2/5 = 3/5
• Bala received 1/3 of 3/5 = 1/3 × 3/5 = 1/5

Answer (a): 1/5 ✓

(b) Fraction of total that Chris received:

Working:

• Ali: 2/5, Bala: 1/5
• Total received by Ali and Bala = 2/5 + 1/5 = 3/5
• Chris received = 1 − 3/5 = 2/5

Answer (b): 2/5 ✓

(c) Total sum of money:

Working:

• Chris received 2/5 of total = $240
• 2/5 × Total = $240
• Total = $240 ÷ 2/5 =$240 × 5/2 = $600

Answer (c): $600 ✓

Marking note: Award 1 mark for (a), 1 mark for (b), and 2 marks for (c). Error carried forward accepted in (b) and (c) if earlier parts are wrong but method is correct.

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Mark Summary

Section	Questions	Marks per Question	Section Total
A	1–10	2	20
B	11–15	4	20
C	16–20	4	20
Total	20	—	60

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End of Answer Key