Primary 5 Mathematics Practice Paper 4

TuitionGoWhere Practice Paper - Mathematics Primary 5 (Answer Key)

Subject: Mathematics
Level: Primary 5
Paper: Practice Paper 4 (Whole Numbers)
Total Marks: 50

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Section A: Multiple Choice Questions (10 marks)

1. Answer: (2) 700 000 [2]

Explanation:
In the number 4 728 391, the digit 7 is in the hundred thousands place.
Place values from right to left: ones, tens, hundreds, thousands, ten thousands, hundred thousands, millions.
Value = 7 × 100 000 = 700 000.

Common mistake: Confusing hundred thousands (700 000) with ten thousands (70 000) or millions (7 000 000).

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2. Answer: (2) 3 850 000 [2]

Explanation:
To round 3 847 256 to the nearest ten thousand:

• Identify the ten thousands digit: 4 (in 3 847 256)
• Look at the digit to its right (thousands place): 7
• Since 7 ≥ 5, round up the ten thousands digit from 4 to 5.
• All digits to the right become 0.
  Result: 3 850 000.

Common mistake: Rounding down because the ten thousands digit is 4, forgetting to check the thousands digit.

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3. Answer: (4) 2 354 768 [2]

Explanation:
Compare numbers digit by digit from the left (millions place):

• All have 2 millions → same
• Hundred thousands: all have 3 → same
• Ten thousands: (1) 4, (2) 5, (3) 4, (4) 5 → 5 is greater than 4, so (2) and (4) are larger
• Thousands: (2) 4, (4) 4 → same
• Hundreds: (2) 6, (4) 7 → 7 > 6, so (4) 2 354 768 is the greatest.

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4. Answer: (1) 5 346 295 [2]

Explanation:
Add the place values:
5 000 000

• 300 000 = 5 300 000
• 40 000 = 5 340 000
• 6 000 = 5 346 000
• 200 = 5 346 200
• 90 = 5 346 290
• 5 = 5 346 295

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5. Answer: (1) 5 654 322 [2]

Explanation:
8 000 000 − 2 345 678
Subtract column by column with regrouping:

  8 000 000
− 2 345 678
-----------
  5 654 322

Check: 5 654 322 + 2 345 678 = 8 000 000 ✓

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Section B: Short Answer Questions (20 marks)

6. Answer: Six million four hundred eight thousand and twenty-nine [2]

Explanation:
Group digits in threes from the right: 6 | 408 | 029

• 6 → Six million
• 408 → Four hundred eight thousand
• 029 → Twenty-nine (zero hundreds not read aloud)
  Key: "and" is used before the last two digits (tens and ones) when there are no hundreds, or before the tens/ones in British convention. In Singapore schools, "and" typically appears before the tens/ones group: "Six million four hundred eight thousand and twenty-nine".

Marking: 1 mark for correct millions/thousands, 1 mark for correct last three digits with "and".

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7. Answer: 8 204 567 [2]

Explanation:
Pattern: 8 234 567, 8 224 567, 8 214 567, ___, 8 194 567
Observe the ten thousands digit decreases by 1 each time: 3 → 2 → 1 → 0 → 9 (in 8 194 567, the ten thousands digit is 9 because it's 8 194 567 = 8 1 9 4 567, wait let me recheck).

Actually: 8 234 567, 8 224 567, 8 214 567
The ten thousands place: 3, 2, 1, 0, then next would be 9 (but 8 194 567 has 9 in ten thousands? No: 8 194 567 = 8 million, 1 hundred thousand, 9 ten thousands... wait).

Let's write place values:
8 234 567 = 8,234,567
8 224 567 = 8,224,567
8 214 567 = 8,214,567
The ten thousands digit goes 3, 2, 1, 0 → 8 204 567
Next: 8 194 567 (ten thousands digit = 9, hundred thousands = 1) ✓

So missing number = 8 204 567.

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8. Answer: 1 298 100 [2]

Explanation:
4 327 × 300 = 4 327 × 3 × 100
= 12 981 × 100
= 1 298 100

Method: Multiply by 3 first, then add two zeros (×100).
4 327 × 3 = 12 981, then × 100 = 1 298 100.

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9. Answer: 982 [2]

Explanation:
7 856 ÷ 8
Long division:

• 78 ÷ 8 = 9 remainder 6
• Bring down 5 → 65 ÷ 8 = 8 remainder 1
• Bring down 6 → 16 ÷ 8 = 2
  Result: 982

Check: 982 × 8 = 7 856 ✓

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10. Answer: 98 000 [2]

Explanation:
2 450 × 40 = 2 450 × 4 × 10
= 9 800 × 10
= 98 000

Alternative: 2 450 × 40 = 2 450 × 4 = 9 800, then × 10 = 98 000.

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11. Answer: 6 245 [2]

Explanation:
January: 3 456 toys
February: 3 456 + 2 789 = 6 245 toys

Working:
3 456

• 2 789

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6 245

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12. Answer: $9 270 [2]

Explanation:
Total spent = $3 280 +$2 450 = $5 730 Money left =$15 000 − $5 730 = **$9 270**

Working:
15 000
− 5 730

9 270

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13. Answer: 380 [2]

Explanation:
4 560 ÷ 12
= 4 560 ÷ 3 ÷ 4 (since 12 = 3 × 4)
= 1 520 ÷ 4
= 380

Or long division: 4 560 ÷ 12 = 380.
Check: 380 × 12 = 4 560 ✓

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14. Answer: 30 868 [2]

Explanation:
Number = (Divisor × Quotient) + Remainder
= (25 × 1 234) + 18
= 30 850 + 18
= 30 868

Working: 1 234 × 25 = 1 234 × 100 ÷ 4 = 123 400 ÷ 4 = 30 850. Then + 18 = 30 868.

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15. Answer: 350 000 [2]

Explanation:
Round each number to the nearest ten:
6 789 → 6 790 (ones digit 9 ≥ 5, round up)
49 → 50 (ones digit 9 ≥ 5, round up)

Estimated product = 6 790 × 50
= 6 790 × 5 × 10
= 33 950 × 10
= 339 500 ≈ 340 000 (if rounding further)

But the question asks to estimate by rounding each number to the nearest ten, then multiply:
6 790 × 50 = 339 500.

However, in Primary 5 estimation, they often expect rounding to one significant figure after the initial rounding, or accept 339 500. Let's check typical P5 expectation: usually they round to nearest ten, then multiply exactly. So 339 500 is the precise estimated value. But many textbooks would round 6 790 to 7 000 and 50 stays 50 → 350 000. Given the options in MCQ style, 350 000 is a common "estimate" answer. Since this is open-ended, I'll provide 339 500 as the direct result of rounding to nearest ten, but note that 350 000 is also acceptable if rounding to one significant figure.

For marking: Accept 339 500 or 350 000 with correct working shown.

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Section C: Structured / Long Answer Questions (20 marks)

16. [4]

(a) Chinese books = 12 345 − 3 456 = 8 889 [2]
(b) Total books = 12 345 + 8 889 = 21 234 [2]

Working for (a):
12 345
− 3 456

8 889

Working for (b):
12 345

• 8 889

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21 234

Marking: 2 marks each part. 1 mark for correct method (subtraction/addition), 1 mark for correct answer. If (a) is wrong but (b) correctly uses (a)'s answer, award method mark for (b).

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17. Answer: 117 [4]

Explanation:
Total chocolates = 8 × 24 = 192
Chocolates given away = 15 × 5 = 75
Chocolates left = 192 − 75 = 117

Step-by-step:

1. 8 × 24 = 192 (total chocolates)
2. 15 × 5 = 75 (given to neighbours)
3. 192 − 75 = 117 (left)

Marking:

• 1 mark: Total chocolates (192)
• 1 mark: Chocolates given (75)
• 1 mark: Subtraction method
• 1 mark: Correct final answer (117)

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18. [4]

(a) Seats occupied on Sunday = 18 472 + 3 258 = 21 730 [2]
(b) Seats not occupied on Sunday = 25 000 − 21 730 = 3 270 [2]

Working for (a):
18 472

• 3 258

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21 730

Working for (b):
25 000
− 21 730

3 270

Marking: 2 marks each part. Follow-through from (a) to (b) allowed.

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19. Answer: 9 011.5 → Wait, whole numbers only. Let me recalculate.

Explanation:
Let the two numbers be L (larger) and S (smaller).
L + S = 15 678
L − S = 2 345

Add the two equations:
2L = 15 678 + 2 345 = 18 023
L = 18 023 ÷ 2 = 9 011.5

But Primary 5 whole numbers should give whole number answers. Let me check the numbers: 15 678 + 2 345 = 18 023, which is odd. This gives a decimal. I need to adjust the question numbers to give a whole number answer.

Correction for the answer key: The question as written gives 9 011.5, which is not a whole number. In a real paper, the numbers would be chosen to give a whole number. For this answer key, I'll show the method and note the issue.

Method (correct approach for whole number problems):
Larger number = (Sum + Difference) ÷ 2
= (15 678 + 2 345) ÷ 2
= 18 023 ÷ 2
= 9 011.5

Since this is not a whole number, there may be a typo in the question. If the sum were 15 678 and difference 2 344, answer = 9 011. If sum = 15 679 and difference = 2 345, answer = 9 012.

For marking purposes: Award full marks for correct method (Sum + Difference) ÷ 2, even if arithmetic yields decimal. The method is the key learning outcome.

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20. [4]

(a) Bottles in 4 weeks = 1 250 × 6 × 4 = 30 000 [2]
(b) Money collected = 30 000 × $3 =$90 000 [2]

Working for (a):
Per day: 1 250
Per week (6 days): 1 250 × 6 = 7 500
4 weeks: 7 500 × 4 = 30 000

Working for (b):
30 000 × $3 = **$90 000**

Marking:

• (a) 1 mark for weekly production (7 500), 1 mark for 4-week total (30 000)
• (b) 1 mark for multiplication method, 1 mark for correct answer with $ sign

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Marking Summary

Section	Questions	Marks per Question	Total Marks
A (MCQ)	1–5	2	10
B (SAQ)	6–15	2	20
C (LAQ)	16–20	4	20
Total	20		50

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Notes for Teachers/Parents

1. Question 15 (Estimation): Accept both 339 500 (direct rounding to nearest ten) and 350 000 (rounding to one significant figure after initial rounding). The key is showing the rounding step.

2. Question 19 (Sum and Difference): The numbers in this version yield a decimal answer. In actual practice, ensure sum + difference is even. The method (Sum + Difference) ÷ 2 for larger number and (Sum − Difference) ÷ 2 for smaller number is the standard heuristic.

3. Working: All multi-mark questions require clear working. Deduct method marks if only answer is given without working.

4. Units: For money questions (12, 20), the $ sign must be included in the final answer.

5. Number notation: Encourage use of spaces (not commas) for thousands separators per Singapore convention: 30 000 not 30,000.