Primary 3 Mathematics Semestral Assessment 2 (End of Year) Paper 1

Primary 3 Mathematics Quiz - Whole Numbers — Answer Key (Version 1)

Total Marks: 50 | Section A: 10 | Section B: 20 | Section C: 20

Section A (Questions 1–5)

1. (3) 7 000 [2] The digit 7 sits in the thousands place of 7 065. "Value of a digit" means the digit multiplied by its place value: $7 \times 1\,000 = 7\,000$. Common mistake: Writing just 7 (that is the digit itself, not its value).

2. (1) 5 098 [2] All four numbers have 5 thousands, so compare the hundreds digit: 0, 8, 8, 9. Since 0 is smallest, 5 098 is the smallest number. Common mistake: Choosing 5 908 (the largest) by misreading the question.

3. (2) 6 405 [2] "six thousand" → 6 in the thousands place; "four hundred" → 4 in the hundreds place; "five" → 5 in the ones place; no tens are named, so 0 goes in the tens place: 6 405. Common mistake: (1) 6 450 swaps the tens and ones.

4. (3) 3 180 [2] Find the difference between terms next to the gap: $3\,210 - 3\,150 = 60$, so the pattern jumps by 30 each time ($30 \times 2 = 60$ across the gap). Then $3\,150 + 30 = 3\,180$. Check: $3\,180 + 30 = 3\,210$. ✓

5. (4) 6 300 [2] To round to the nearest hundred, look at the tens digit. In 6 278 the tens digit is 7, and $7 \geq 5$, so round up: $6\,278 \rightarrow 6\,300$. Common mistake: (2) 6 270 comes from looking at the ones digit instead.

Section B (Questions 6–15)

6. 300 [2] In 9 384, the digit 3 is in the hundreds place, so its value is $3 \times 100 = 300$.

7. Seven thousand and nineteen [2] 7 019 = 7 thousands, 0 hundreds, 1 ten, 9 ones. Say the thousands part ("seven thousand"), then the rest ("and nineteen"). Accept "seven thousand, nineteen". Common mistake: Writing "seven thousand and ninety" (mixing up 19 and 90).

8. 4 765, 4 756, 4 657, 4 576 [2] All have 4 thousands. Compare hundreds: 7, 7, 6, 5 → the two 7-hundred numbers come first. Compare their tens: 6 > 5, so 4 765 before 4 756. Then 4 657, then 4 576. Marks: 1 mark for a partly correct order, 2 marks for the full correct order.

9. 7 300 [2] The pattern decreases: $8\,500 - 7\,900 = 600$ and $6\,700 - 6\,100 = 600$, so subtract 600 each time: $7\,900 - 600 = 7\,300$. Check: $7\,300 - 600 = 6\,700$. ✓

10. 5 350 [2] To round to the nearest ten, look at the ones digit. In 5 347 the ones digit is 7, and $7 \geq 5$, so round up: $5\,347 \rightarrow 5\,350$.

11. 8 520 [2] For the largest number, place the biggest digit in the highest place: 8 (thousands), 5 (hundreds), 2 (tens), 0 (ones) → 8 520.

12. 4 132 [2] An even number ends in 0, 2, 4, 6 or 8. Only 4 132 ends in an even digit (2); the others end in 3, 1 and 3, so they are odd. 4 132 is therefore the smallest even number. Common mistake: Writing 4 123 — it is smaller than 4 132, but it is odd, so it fails the "even" condition. Both conditions must be true.

13. 5 293 [2] Add each part into its place: 5 thousands, 2 hundreds, 9 tens, 3 ones → 5 293.

14. > [2] Both numbers have 7 thousands and 8 hundreds. Compare the tens: 9 > 4, so $7\,894 > 7\,849$.

15. 1 125 [2] The rule says add 25 each time: $1\,100 + 25 = 1\,125$. Check: $1\,125 + 25 = 1\,150$. ✓

Section C (Questions 16–20)

16. (a) 3 508 (b) Three thousand, five hundred and eight [4] (a) Build the number place by place: 3 thousands → 3___, 5 hundreds → 35__, 0 tens → 350_, 8 ones → 3 508. [2] (b) Read it back in words: "three thousand, five hundred and eight". Accept "three thousand five hundred and eight". [2] Common mistake: Leaving out the 0 tens and writing 358 — a 4-digit number must keep the 0 as a placeholder.

17. (a) 2 540, 2 450, 2 405, 2 054 (b) Cai Ling (c) Amy [4] (a) All have 2 thousands. Compare hundreds: 5, 4, 4, 0 → 2 540 first, then the two 4-hundred numbers, then 2 054. Compare tens of those two: 5 > 0, so 2 450 before 2 405. [2] (b) The greatest amount, 2 540, belongs to Cai Ling. [1] (c) The second amount, 2 450, belongs to Amy. [1] Marking note: Award (a) 1 mark if only one pair is swapped.

18. (a) 3 800 (b) 4 000 [4] (a) To round to the nearest hundred, look at the tens digit. In 3 762 the tens digit is 6, and $6 \geq 5$, so round up: $3\,762 \rightarrow 3\,800$. [2] (b) To round to the nearest thousand, look at the hundreds digit. In 3 762 the hundreds digit is 7, and $7 \geq 5$, so round up: $3\,762 \rightarrow 4\,000$. This matches the poster's "about 4 000 books". [2] Teaching note: Rounding always checks the digit immediately to the right of the place you are rounding to.

19. (a) 135 and 145 (b) 155 [4] (a) The pattern adds 10 each time: $125 + 10 = 135$, then $135 + 10 = 145$. [2] (b) Continue counting positions: 1st = 105, 2nd = 115, 3rd = 125, 4th = 135, 5th = 145, 6th = $145 + 10 = 155$. [2] Common mistake: Calling 135 the 6th number by forgetting the pattern starts at 105, not 0.

20. (a) 9 742 (b) 2 479 [4] (a) An even number must end in an even digit: 2 or 4. Try each ending and arrange the remaining digits from largest to smallest in front:

• Ending in 2: 9 742
• Ending in 4: 9 724 Since $9\,742 > 9\,724$, the largest even number is 9 742. [2] (b) An odd number must end in an odd digit: 7 or 9. Arrange the remaining digits from smallest to largest in front:
• Ending in 7: 2 497
• Ending in 9: 2 479 Since $2\,479 < 2\,497$, the smallest odd number is 2 479. [2] Teaching note: Fix the units digit first (it controls even/odd), then maximise or minimise the remaining places. Always test every allowed units digit — the best-looking choice is not always the answer.

Mark totals check: Section A $5 \times 2 = 10$; Section B $10 \times 2 = 20$; Section C $5 \times 4 = 20$; Grand total $= 50$ marks.