Primary 4 Mathematics Practice Paper 4

TuitionGoWhere Practice Paper - Mathematics Primary 4 (Answer Key)

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

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Section A: Multiple-Choice Questions (10 marks)

1. In the number 64,287, which digit is in the thousands place? [2]

Answer: (2) 4

Explanation:
The place values from right to left are: ones, tens, hundreds, thousands, ten thousands.
64,287 = 6 ten thousands, 4 thousands, 2 hundreds, 8 tens, 7 ones.
The digit in the thousands place is 4.

Common mistake: Confusing "thousands place" with "ten thousands place" (which would be 6).

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2. What does the digit 5 stand for in 35,912? [2]

Answer: (4) 5000

Explanation:
35,912 = 3 ten thousands, 5 thousands, 9 hundreds, 1 ten, 2 ones.
The digit 5 is in the thousands place, so its value is 5 × 1,000 = 5,000.

Common mistake: Choosing 500 (hundreds place) or 50 (tens place). Remember: "stand for" means the value of the digit, not the digit itself.

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3. Round 48,372 to the nearest hundred. [2]

Answer: (2) 48,400

Explanation:
To round to the nearest hundred, look at the tens digit (7).
Since 7 ≥ 5, we round up the hundreds digit (3 → 4).
48,372 → 48,400.

Common mistake: Rounding to the nearest thousand (48,000) or rounding down because the hundreds digit is 3.

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4. Which of the following numbers when rounded to the nearest thousand gives 72,000? [2]

Answer: (3) 72,450

Explanation:
When rounding to the nearest thousand, look at the hundreds digit.

• 71,450 → hundreds digit is 4 (< 5) → rounds to 71,000 ✗
• 71,550 → hundreds digit is 5 (≥ 5) → rounds to 72,000 ✓
• 72,450 → hundreds digit is 4 (< 5) → rounds to 72,000 ✓
• 72,550 → hundreds digit is 5 (≥ 5) → rounds to 73,000 ✗

Both 71,550 and 72,450 round to 72,000. However, only 72,450 is among the options as (3).
(Note: Option (2) is 71,550 which also works, but the question asks "Which of the following" implying one correct answer. In standard Singapore exam format, 72,450 is the intended answer as it's closer to 72,000.)

Marking note: If both (2) and (3) are mathematically correct, accept either with explanation.

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5. 53,000 + 4,800 + 60 + 9 = ________ [2]

Answer: (1) 57,869 (all options are identical; this is a straightforward computation)

Working:
53,000

• 4,800
• 60
• 9
  = 57,869

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Section B: Short-Answer Questions (20 marks)

6. Write sixty-two thousand, four hundred and five in numerals. [2]

Answer: 62,405

Explanation:

• "Sixty-two thousand" = 62,000
• "Four hundred" = 400
• "Five" = 5
• Total = 62,000 + 400 + 5 = 62,405

Common mistake: Writing 62,450 (confusing "four hundred and five" with "four hundred fifty") or 62,045 (omitting the hundreds).

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7. In 81,503, the digit 8 is in the ________________ place. [2]

Answer: ten thousands

Explanation:
81,503 = 8 ten thousands, 1 thousand, 5 hundreds, 0 tens, 3 ones.
The digit 8 is in the ten thousands place.

Common mistake: Writing "thousands" (that's the digit 1) or "eighty thousands" (describing the value, not the place).

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8. What is the value of the digit 7 in 47,286? [2]

Answer: 7,000 (or 7000)

Explanation:
47,286 = 4 ten thousands, 7 thousands, 2 hundreds, 8 tens, 6 ones.
The digit 7 is in the thousands place.
Value = 7 × 1,000 = 7,000.

Common mistake: Writing "7" (the digit itself) or "thousands" (the place, not the value).

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9. Round 29,645 to the nearest ten. [2]

Answer: 29,650

Explanation:
Look at the ones digit (5).
Since 5 ≥ 5, round up the tens digit (4 → 5).
29,645 → 29,650.

Common mistake: Rounding to the nearest hundred (29,600) or rounding down to 29,640.

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10. Round 63,821 to the nearest thousand. [2]

Answer: 64,000

Explanation:
Look at the hundreds digit (8).
Since 8 ≥ 5, round up the thousands digit (3 → 4).
63,821 → 64,000.

Common mistake: Rounding down to 63,000 (looking at the thousands digit 3 instead of the hundreds digit 8).

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11. A number rounded to the nearest hundred is 54,300. What is the smallest possible value of this number? [2]

Answer: 54,250

Explanation:
When rounding to the nearest hundred gives 54,300, the original number must be in the range:
54,250 ≤ number < 54,350

The smallest possible value is 54,250 (since 54,250 rounds up to 54,300).

Common mistake: Answering 54,200 (that would round to 54,200) or 54,300 (that's the rounded value, not the original).

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12. A number rounded to the nearest thousand is 18,000. What is the greatest possible value of this number? [2]

Answer: 18,499

Explanation:
When rounding to the nearest thousand gives 18,000, the original number must be in the range:
17,500 ≤ number < 18,500

The greatest possible value is 18,499 (since 18,500 would round up to 19,000).

Common mistake: Answering 18,500 (that rounds to 19,000) or 18,000 (the rounded value).

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13. Find the sum of 24,567 and 38,432. [2]

Answer: 62,999

Working:
24,567

• 38,432

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62,999

Check: 24,567 + 38,432 = 62,999 ✓

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14. Find the difference between 85,000 and 47,629. [2]

Answer: 37,371

Working:
85,000

• 47,629

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37,371

Check: 37,371 + 47,629 = 85,000 ✓

Common mistake: Forgetting to regroup (borrow) across zeros.
85,000 - 47,629:

• Borrow from 8 ten thousands → 7 ten thousands, 10 thousands
• Borrow from 10 thousands → 9 thousands, 10 hundreds
• Borrow from 10 hundreds → 9 hundreds, 10 tens
• Borrow from 10 tens → 9 tens, 10 ones
  Then subtract: 10-9=1, 9-2=7, 9-6=3, 9-7=2, 7-4=3 → 37,371

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15. Complete the number pattern. [2]

42,000, 43,500, 45,000, ________, 48,000

Answer: 46,500

Explanation:
Find the difference between consecutive terms:
43,500 - 42,000 = 1,500
45,000 - 43,500 = 1,500

The pattern increases by 1,500 each time.
Next term: 45,000 + 1,500 = 46,500
Check: 46,500 + 1,500 = 48,000 ✓

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

16. Singapore's population density is about 8,358 people per square kilometre. [4]

(a) Round this number to the nearest hundred.
Answer: 8,400
Working: Tens digit is 5 (≥ 5), so round up hundreds digit (3 → 4). 8,358 → 8,400.

(b) Round this number to the nearest thousand.
Answer: 8,000
Working: Hundreds digit is 3 (< 5), so round down. 8,358 → 8,000.

(c) What is the difference between the two rounded numbers?
Answer: 400
Working: 8,400 - 8,000 = 400.

Marking: 1 mark each for (a) and (b), 2 marks for (c) (1 mark for correct subtraction, 1 mark for correct answer).

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17. The table below shows the number of visitors to three museums in Singapore last year. [4]

Museum	Number of Visitors
National Museum of Singapore	52,487
Asian Civilisations Museum	38,921
Singapore Art Museum	45,634

(a) Which museum had the greatest number of visitors?
Answer: National Museum of Singapore
Reasoning: 52,487 > 45,634 > 38,921.

(b) Find the total number of visitors to all three museums.
Answer: 137,042
Working:
52,487

• 38,921
• 45,634

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137,042

(c) How many more visitors did the National Museum of Singapore have than the Asian Civilisations Museum?
Answer: 13,566
Working: 52,487 - 38,921 = 13,566.

Marking: 1 mark each for (a), (b), (c) with working; 1 mark for correct final answer in (b) and (c).

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18. A housing estate has 5 blocks of flats. [4]

Block 1: 12,345 residents
Block 2: 13,287 residents
Block 3: 11,956 residents
Block 4: 14,023 residents
Block 5: 12,789 residents

(a) Which block has the most residents?
Answer: Block 4
Reasoning: 14,023 is the largest among the five numbers.

(b) Find the total number of residents in all 5 blocks.
Answer: 64,400
Working:
12,345

• 13,287
• 11,956
• 14,023
• 12,789

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64,400

(c) Round the total number of residents to the nearest thousand.
Answer: 64,000
Working: Hundreds digit is 4 (< 5), so round down. 64,400 → 64,000.

Marking: 1 mark for (a), 2 marks for (b) (1 mark for correct addition method, 1 mark for correct answer), 1 mark for (c).

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19. Study the number pattern below. [4]

7, 14, 28, 56, ________, ________

(a) Write the next two numbers in the pattern.
Answer: 112, 224
Working: Each term is multiplied by 2 (×2).
56 × 2 = 112
112 × 2 = 224

(b) What is the rule for this pattern?
Answer: Multiply by 2 (or "Each number is double the previous number" / "×2")

(c) Will the number 448 appear in this pattern? Explain your answer.
Answer: Yes.
Explanation: Continuing the pattern: 224 × 2 = 448. Since 448 is obtained by multiplying the previous term by 2, it will appear as the next term after 224.

Marking: 1 mark each for the two numbers in (a), 1 mark for (b), 1 mark for (c) with correct explanation.

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20. Mr Tan bought a car for $68,450. He paid a deposit of$15,000 and the rest in monthly instalments over 5 years. [4]

(a) How much did he pay in instalments altogether?
**Answer: $53,450** *Working:*$68,450 - $15,000 =$53,450.

(b) How much was each monthly instalment if he paid the same amount every month?
Answer: $890.83** (or$890.83... accept $891 if rounding to nearest dollar is implied, but exact is$53,450 ÷ 60 = $890.833...) *Working:* 5 years = 5 × 12 = 60 months.$53,450 ÷ 60 = $890.833... ≈ **$890.83 (to 2 decimal places)

Note for Primary 4: This division gives a decimal. In Primary 4, students learn division with remainders. The expected answer may be:
$53,450 ÷ 60 =$890 remainder $50, or$890.83.
Accept either: "$890 remainder$50" or "$890.83" or "$890.80" (if using 2 d.p. convention).

(c) Round the monthly instalment to the nearest ten dollars.
**Answer: $890** (if using$890.83) or **$890** (if using$890)
Working: $890.83 → tens digit is 9, ones digit is 0 (< 5), so round down to$890.
If using $890 exactly: already at nearest ten →$890.

Marking: 1 mark for (a), 2 marks for (b) (1 mark for correct method: ÷ 60, 1 mark for correct answer), 1 mark for (c).

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Total: 50 marks