Primary 5 Mathematics Whole Numbers Quiz

Primary 5 Mathematics Quiz - Whole Numbers - Answer Key (Version 1 of 5)

Syllabus-aligned generated content; not past-paper derived.

Answer 1.

Final answer: Seven million, three hundred and five thousand, two hundred and four. (2 marks)

Teaching notes: Read the number in groups of three digits from the left: 7 (millions), 305 (thousands), 204 (ones). Say each group with its place name except the last group. Common mistakes: writing "seven million three hundred five thousand two hundred four" without "and", or missing the zero in "forty" position — 7,305,204 has no ten-thousands digit, so nothing is read there.

Answer 2.

Final answer: 70,000 (2 marks)

Method: Locate the digit 7 in 9,274,506. Counting places from the right: ones, tens, hundreds, thousands, ten thousands. The 7 sits in the ten-thousands place, so its value is 7 × 10,000 = 70,000. Common mistake: answering "ten thousands" (that is the place name, not the value).

Answer 3.

Final answer: 3,405,210; 3,450,120; 3,451,020 (2 marks)

Method: All numbers share the millions digit 3, so compare the hundred-thousands digit: all are 4. Compare the ten-thousands digit: 0, 5, 5. The number with 0 (3,405,210) is smallest. For the two with 5, compare the thousands digit: 0 versus 1, so 3,450,120 comes before 3,451,020. Marking: 1 mark for correct order attempt, 2 marks fully correct.

Answer 4.

Final answer: 38,000 (2 marks)

Method: Multiplying by 1000 moves every digit three places to the left (adds three zeros): 38 → 38,000. Teaching point: the digits themselves never change; only their place values grow.

Answer 5.

Final answer: 16 (2 marks)

Method: Follow the order of operations (division before subtraction): 8 ÷ 2 = 4, then 20 − 4 = 16. Common mistake: subtracting first to get 12 ÷ 2 = 6. Brackets are absent, so division is done first.

Answer 6.

Final answer: 6,040,715 (3 marks)

Method: Build the number place by place: millions = 6; hundred-thousands = 0; ten-thousands = 4; thousands = 0; hundreds = 7; tens = 1; ones = 5 → 6,040,715. Teaching note: when a spoken group is skipped (no "hundred thousand" mentioned), write 0 in that place. Marking: 1 mark for correct millions placement, 1 mark for 040 grouping, 1 mark fully correct.

Answer 7.

Expected chart features: seven columns labelled Millions, Hundred Thousands, Ten Thousands, Thousands, Hundreds, Tens, Ones with digits 2, 4, 6, 8, 0, 5, 3 beneath them, forming 2,468,053.

(a) Final answer: 2,468,053 (1 mark)

(b) Final answer: 2,500,000 (2 marks)

Method for (b): To round to the nearest hundred thousand, look at the ten-thousands digit (6). Since 6 is 5 or more, round up: the hundred-thousands digit increases from 4 to 5 and all smaller places become zeros → 2,500,000. Common mistake: rounding down to 2,400,000 by ignoring the check digit.

Answer 8.

(a) Final answer: 5,846,000 (1 mark)

(b) Final answer: 5,800,000 (2 marks)

Method: (a) Nearest thousand: check the hundreds digit (2). Less than 5, so keep 846 and change smaller places to zeros → 5,846,000. (b) Nearest hundred thousand: check the ten-thousands digit (4). Less than 5, so round down: keep the 8 in the hundred-thousands place → 5,800,000. Marking for (b): 1 mark for correct check digit identified, 1 mark for correct rounded value.

Answer 9.

Final answer: 80 (3 marks)

Method: Cancel matching zeros before dividing: 720,000 ÷ 9000 = 720 ÷ 9 after removing three zeros from both numbers. Then 72 ÷ 9 = 8, and one extra zero remains, giving 80. Alternatively: 720,000 = 72 × 10,000 and 9000 = 9 × 1000, so the quotient is (72 ÷ 9) × (10,000 ÷ 1000) = 8 × 10 = 80. Marking: 1 mark for cancelling zeros correctly, 1 mark for 72 ÷ 9 = 8, 1 mark for final answer 80.

Answer 10.

Final answer: 24 (3 marks)

Method: Brackets first: 11 − 5 = 6. Then work left to right for division and multiplication: 36 ÷ 6 = 6, then 6 × 4 = 24. Teaching point: ÷ and × have equal priority, so solve them in the order they appear. Common mistake: doing 6 × 4 before dividing, which happens to give the same answer here, but the correct written sequence must show 36 ÷ 6 first.

Answer 11.

Final answer: 5 × (7 − 3) + 2 = 22 (3 marks)

Check: Brackets first: 7 − 3 = 4. Then 5 × 4 = 20, and 20 + 2 = 22. ✓

Reasoning: Without brackets, 5 × 7 − 3 + 2 = 35 − 3 + 2 = 34, which is too big. We need the multiplication to act on a smaller number, so the brackets must enclose 7 − 3. Testing other placements ((5 × 7 − 3) + 2 = 34; 5 × 7 − (3 + 2) = 30; 5 × (7 − 3 + 2) = 30) confirms this is the only solution. Marking: 1 mark for sensible bracket trial, 2 marks for correct placement with verification.

Answer 12.

(a) Final answer: Subtract 50,000 each time. (1 mark)

(b) Final answer: 1,050,000; 1,000,000 (2 marks)

Method: Check the differences: 1,200,000 − 1,150,000 = 50,000 and

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# Primary 5 Mathematics Quiz - Whole Numbers - Answer Key (Version 1 of 5)

*Syllabus-aligned generated content; not past-paper derived.*

## Answer 1.
**Final answer:** Seven million, three hundred and five thousand, two hundred and four. (2 marks)

**Teaching notes:** Read the number in groups of three digits from the left: 7 (millions), 305 (thousands), 204 (ones). Say each group with its place name except the last group. Common mistakes: missing the zero in the ten-thousands position — 7,305,204 has no ten-thousands digit, so nothing is read there.

## Answer 2.
**Final answer:** 70,000 (2 marks)

**Method:** Locate the digit 7 in 9,274,506. Counting places from the right: ones, tens, hundreds, thousands, ten thousands. The 7 sits in the ten-thousands place, so its value is 7 × 10,000 = 70,000. Common mistake: answering "ten thousands" (that is the place name, not the value).

## Answer 3.
**Final answer:** 3,405,210; 3,450,120; 3,451,020 (2 marks)

**Method:** All numbers share the millions digit 3, so compare the hundred-thousands digit: all are 4. Compare the ten-thousands digit: 0, 5, 5. The number with 0 (3,405,210) is smallest. For the two with 5, compare the thousands digit: 0 versus 1, so 3,450,120 comes before 3,451,020. Marking: 1 mark for correct order attempt, 2 marks fully correct.

## Answer 4.
**Final answer:** 38,000 (2 marks)

**Method:** Multiplying by 1000 moves every digit three places to the left (adds three zeros): 38 → 38,000. Teaching point: the digits themselves never change; only their place values grow.

## Answer 5.
**Final answer:** 16 (2 marks)

**Method:** Follow the order of operations (division before subtraction): 8 ÷ 2 = 4, then 20 − 4 = 16. Common mistake: subtracting first to get 12 ÷ 2 = 6. Brackets are absent, so division is done first.

## Answer 6.
**Final answer:** 6,040,715 (3 marks)

**Method:** Build the number place by place: millions = 6; hundred-thousands = 0; ten-thousands = 4; thousands = 0; hundreds = 7; tens = 1; ones = 5 → 6,040,715. Teaching note: when a spoken group is skipped (no "hundred thousand" mentioned), write 0 in that place. Marking: 1 mark for correct millions placement, 1 mark for 040 grouping, 1 mark fully correct.

## Answer 7.
Expected chart features: seven columns labelled Millions, Hundred Thousands, Ten Thousands, Thousands, Hundreds, Tens, Ones with digits 2, 4, 6, 8, 0, 5, 3 beneath them, forming 2,468,053.

**(a)** Final answer: 2,468,053 (1 mark)

**(b)** Final answer: 2,500,000 (2 marks)

**Method for (b):** To round to the nearest hundred thousand, look at the ten-thousands digit (6). Since 6 is 5 or more, round up: the hundred-thousands digit increases from 4 to 5 and all smaller places become zeros → 2,500,000. Common mistake: rounding down to 2,400,000 by ignoring the check digit.

## Answer 8.
**(a)** Final answer: 5,846,000 (1 mark)

**(b)** Final answer: 5,800,000 (2 marks)

**Method:** (a) Nearest thousand: check the hundreds digit (2). Less than 5, so keep 846 and change smaller places to zeros → 5,846,000. (b) Nearest hundred thousand: check the ten-thousands digit (4). Less than 5, so round down: keep the 8 in the hundred-thousands place → 5,800,000. Marking for (b): 1 mark for correct check digit identified, 1 mark for correct rounded value.

## Answer 9.
**Final answer:** 80 (3 marks)

**Method:** Cancel matching zeros before dividing: 720,000 ÷ 9000 = 720 ÷ 9 after removing three zeros from both numbers. Then 72 ÷ 9 = 8, and one extra zero remains, giving 80. Alternatively: 720,000 = 72 × 10,000 and 9000 = 9 × 1000, so the quotient is (72 ÷ 9) × (10,000 ÷ 1000) = 8 × 10 = 80. Marking: 1 mark for cancelling zeros correctly, 1 mark for 72 ÷ 9 = 8, 1 mark for final answer 80.

## Answer 10.
**Final answer:** 24 (3 marks)

**Method:** Brackets first: 11 − 5 = 6. Then work left to right for division and multiplication: 36 ÷ 6 = 6, then 6 × 4 = 24. Teaching point: ÷ and × have equal priority, so solve them in the order they appear. Common mistake: doing 6 × 4 before dividing; here it happens to give the same answer, but the correct written sequence must show 36 ÷ 6 first.

## Answer 11.
**Final answer:** 5 × (7 − 3) + 2 = 22 (3 marks)

**Check:** Brackets first: 7 − 3 = 4. Then 5 × 4 = 20, and 20 + 2 = 22. ✓

**Reasoning:** Without brackets, 5 × 7 − 3 + 2 = 35 − 3 + 2 = 34, which is too big. We need the multiplication to act on a smaller number, so the brackets must enclose 7 − 3. Testing other placements ((5 × 7 − 3) + 2 = 34; 5 × 7 − (3 + 2) = 30; 5 × (7 − 3 + 2) = 30) confirms this is the only solution. Marking: 1 mark for sensible bracket trial, 2 marks for correct placement with verification.

## Answer 12.
**(a)** Final answer: Subtract 50,000 each time. (1 mark)

**(b)** Final answer: 1,050,000; 1,000,000 (2 marks)

**Method:** Check the differences: 1,200,000 − 1,150,000 = 50,000 and 1,150,000 − 1,100,000 = 50,000, so the rule is a constant decrease of 50,000. Continue: 1,100,000 − 50,000 = 1,050,000, then 1,050,000 − 50,000 = 1,000,000. Marking: 1 mark per correct number in (b); both must follow the stated rule.

## Answer 13.
**Final answer:** 7,000 posters (3 marks)

**Working:** Posters per hour × number of hours = 350 × 20. Break it down: 350 × 20 = 350 × 2 × 10 = 700 × 10 = 7,000. Marking: 1 mark for correct operation chosen (multiplication), 1 mark for accurate working, 1 mark for final answer with units.

## Answer 14.
**Final answer:** 250 stamps (3 marks)

**Working:** Stamps given away: 250 × 8 = 2,000. Stamps remaining: 4,500 − 2,000 = 2,500. Stamps per album: 2,500 ÷ 10 = 250. Marking: 1 mark for 2,000 given away, 1 mark for 2,500 remaining, 1 mark for 250 per album.

## Answer 15.
**Final answer:** 240,000 (3 marks)

**Working:** Round 5,982 to the nearest thousand: the hundreds digit is 9 (5 or more), so round up → 6,000. Round 41 to the nearest ten: the ones digit is 1 (less than 5), so round down → 40. Multiply: 6,000 × 40 = 240,000. Marking: 1 mark for each correct rounded value, 1 mark for the product.

## Answer 16.
**Final answer:** 68 books (4 marks)

**Working:** Total books received: 12 × 145 = 1,740. Books remaining after removing damaged ones: 1,740 − 380 = 1,360. Books per shelf: 1,360 ÷ 20 = 68. Marking: 1 mark for 1,740, 1 mark for 1,360, 1 mark for correct division setup, 1 mark for final answer of 68.

## Answer 17.
**Final answer:** 50 (4 marks)

**Working (work backwards):** Final answer was 130, obtained by dividing by 15, so before dividing: 130 × 15 = 1,950. Before adding 450: 1,950 − 450 = 1,500. Before multiplying by 30: 1,500 ÷ 30 = 50. **Check forwards:** 50 × 30 = 1,500; 1,500 + 450 = 1,950; 1,950 ÷ 15 = 130. ✓ Marking: 1 mark for reversing the last operation, 1 mark for reversing the middle step, 1 mark for reversing the first step, 1 mark for final answer 50.

## Answer 18.
**Final answer:** 6,000 more English books than Malay books (4 marks)

**Working (unit method):** Let Malay books = 1 unit. Chinese = 3 units. English = twice Chinese = 6 units. Total units: 1 + 3 + 6 = 10 units. One unit: 12,000 ÷ 10 = 1,200 books. English books: 6 × 1,200 = 7,200. Malay books: 1,200. Difference: 7,200 − 1,200 = 6,000. Marking: 1 mark for correct unit model (1 : 3 : 6), 1 mark for finding one unit = 1,200, 1 mark for computing 7,200 and 1,200, 1 mark for difference of 6,000.

## Answer 19.
**(a)** Final answer: 2,365,000 (2 marks)

**(b)** Final answer: 2,374,999 (2 marks)

**Method:** A number rounds to 2,370,000 (nearest ten thousand) when it lies from halfway up to just below the next halfway point. Halfway below: 2,370,000 − 5,000 = 2,365,000 (smallest possible). Largest possible: the greatest whole number before 2,370,000 + 5,000 = 2,375,000, which is 2,374,999. Marking: 2 marks per part; deduct 1 mark if the boundary logic (±5,000) is misapplied but the idea is present.

## Answer 20.
**(a)** Final answer: 39 boxes (3 marks)

**(b)** Final answer: 4,500 flyers (1 mark)

**Working for (a):** Total distributed over two days: 13,500 + 9,000 = 22,500. Flyers remaining: 42,000 − 22,500 = 19,500. Boxes needed: 19,500 ÷ 500 = 39. Marking: 1 mark for 22,500, 1 mark for 19,500 remaining, 1 mark for 39 boxes.

**Working for (b):** Difference between days: 13,500 − 9,000 = 4,500 flyers.

**End of Answer Key**