Primary 4 Mathematics Whole Numbers Quiz

Primary 4 Mathematics Quiz - Whole Numbers

Answer Key

Section A: Place Value and Number Recognition

1. 3

• Working: In 63,825, the places from left to right are: 6 (ten thousands), 3 (thousands), 8 (hundreds), 2 (tens), 5 (ones). The digit in the thousands place is 3.
• Marking: 2 marks for correct answer. 1 mark if student identifies the position correctly but writes the wrong digit.

2. 7,000

• Working: In 47,306, the digit 7 is in the thousands place. So 7 stands for 7,000.
• Marking: 2 marks for correct answer. Accept "7 thousand" or "7000".

3. 82,509

• Working: Eighty-two thousand = 82,000; five hundred = 500; nine = 9. Combined: 82,000 + 500 + 9 = 82,509.
• Marking: 2 marks for correct answer. Common mistake: writing 82,590 or 82,059.

4. Ninety-one thousand and forty-three

• Working: 91,043 → 91,000 (ninety-one thousand) + 43 (forty-three) = "Ninety-one thousand and forty-three."
• Marking: 2 marks for correct answer. Accept "Ninety-one thousand, forty-three." Common mistake: writing "Ninety-one thousand and four-three" or omitting "and."

5. 51,402, 51,987, 52,140, 52,301

• Working: Compare digit by digit from the left. All numbers start with 5 in the ten thousands place. In the thousands place: 1, 1, 2, 2. So 51,402 and 51,987 come first. Comparing hundreds: 4 < 9, so 51,402 < 51,987. Then 52,140 and 52,301: hundreds place 1 < 3, so 52,140 < 52,301.
• Marking: 2 marks for fully correct order. 1 mark if at least two numbers are in the correct relative position.

Section B: Rounding Numbers

6. 38,500

• Working: To round 38,467 to the nearest hundred, look at the tens digit (6). Since 6 ≥ 5, round up the hundreds digit from 4 to 5. Replace tens and ones with 0. Answer: 38,500.
• Marking: 2 marks for correct answer. Common mistake: 38,470 (rounding to nearest ten instead).

7. 73,000

• Working: To round 72,581 to the nearest thousand, look at the hundreds digit (5). Since 5 ≥ 5, round up the thousands digit from 2 to 3. Replace hundreds, tens and ones with 0. Answer: 73,000.
• Marking: 2 marks for correct answer. Common mistake: 72,000 (not rounding up when digit is 5).

8. 45,615

• Working: If a number rounded to the nearest ten is 45,620, the original number must be between 45,615 and 45,624 (inclusive of 45,615, exclusive of 45,625). The smallest possible value is 45,615.
• Marking: 2 marks for correct answer. Common mistake: 45,621 or 45,610.

9. 63,449

• Working: If a number rounded to the nearest hundred is 63,400, the original number must be between 63,400 and 63,449 (since 63,450 would round to 63,500). The greatest possible value is 63,449.
• Marking: 2 marks for correct answer. Common mistake: 63,450 or 63,499.

10. 27,538 ≈ 28,000

• Working: To round 27,538 to the nearest thousand, look at the hundreds digit (5). Since 5 ≥ 5, round up the thousands digit from 7 to 8. Answer: 28,000.
• Marking: 2 marks for correct answer with ≈ symbol used. Common mistake: 27,000 (not rounding up).

Section C: Number Patterns and Sequences

11. 12,950

• Working: The pattern increases by 200 each time. 12,350 + 200 = 12,550; 12,550 + 200 = 12,750; 12,750 + 200 = 12,950.
• Marking: 2 marks for correct answer. 1 mark if student identifies the pattern (+200) but makes an arithmetic error.

12. 70,000

• Working: The pattern decreases by 5,000 each time. 85,000 − 5,000 = 80,000; 80,000 − 5,000 = 75,000; 75,000 − 5,000 = 70,000.
• Marking: 2 marks for correct answer.

13. 5,700

• Working: The pattern increases by 300 each time. 1st: 4,200; 2nd: 4,500; 3rd: 4,800; 4th: 5,100; 5th: 5,400; 6th: 5,700.
• Marking: 2 marks for correct answer. 1 mark if student identifies the pattern (+300) but makes an arithmetic error.

14. 30,100

• Working: The pattern increases by 50 each time. 30,000 + 50 = 30,050; 30,050 + 50 = 30,100; 30,100 + 50 = 30,150; 30,150 + 50 = 30,200.
• Marking: 2 marks for correct answer.

15. 23,000

• Working: 1st: 15,000; 2nd: 17,000; 3rd: 19,000; 4th: 21,000; 5th: 23,000. (Add 2,000 each time.)
• Marking: 2 marks for correct answer. 1 mark if student identifies the pattern but makes an arithmetic error.

Section D: Comparing, Ordering and Problem Solving

16. 64,205 > 64,025

• Working: Compare digit by digit from the left. Both have 6 (ten thousands) and 4 (thousands). In the hundreds place: 2 > 0. So 64,205 > 64,025.
• Marking: 2 marks for correct symbol.

17. 7, 8 or 9

• Working: For 5_,318 > 56,318, the missing digit in the thousands place must be greater than 6. So the digit can be 7, 8, or 9.
• Marking: 2 marks for all three correct digits. 1 mark if only one or two correct digits are given.

18. 40,703

• Working: Ten thousands place = 4; thousands place = 0; hundreds place = 7; tens place = 0; ones place = 3. The number is 40,703.
• Marking: 2 marks for correct answer. Common mistake: 47,003 (confusing hundreds with thousands).

19. (a) 50,000 | (b) 55,000

• Working for (a): To round 49,752 to the nearest thousand, look at the hundreds digit (7). Since 7 ≥ 5, round up: 49,752 → 50,000.
• Working for (b): Estimated new population = 50,000 + 5,000 = 55,000.
• Marking: 1 mark for (a), 2 marks for (b) — 1 mark for correct working, 1 mark for correct final answer.

20. (a) 28,999, 28,450, 27,503 | (b) 84,952 books

• Working for (a): Comparing the three numbers: 28,999 > 28,450 > 27,503.
• Working for (b): 28,450 + 28,999 + 27,503 = 57,449 + 27,503 = 84,952.
• Marking: 1 mark for (a) correct order. 2 marks for (b) — 1 mark for correct addition working, 1 mark for correct final answer. Common mistake: misalignment of place values in addition.

Total: 40 marks