Primary 3 Mathematics Semestral Assessment 1 (Mid-Year) Paper 4

Answer Key and Marking Scheme

Subject: Mathematics
Level: Primary 3
Paper: SA1 Practice Paper (Version 4 of 5)
Topic: Whole Numbers

Section A: Multiple Choice Questions (10 marks)

1. (3)
Reasoning: The digit 8 is in the hundreds place. Its value is $8 \times 100 = 800$.
Common Mistake: Choosing (1) which is the digit itself, not the value.

2. (4)
Reasoning: Compare the digits from left to right.
All numbers start with 3 (thousands).
Look at hundreds: 0, 8, 9, 0.
The numbers with 0 in the hundreds place are 3,098 and 3,089.
Compare tens: 9 (in 3,098) and 8 (in 3,089).
8 is smaller than 9, so 3,089 is the smallest.

3. (2)
Reasoning:
6,000 (Thousands)
0 (Hundreds - none mentioned)
40 (Tens)
9 (Ones)
Result: 6,049.

4. (2)
Reasoning: Rounding to the nearest ten. Look at the ones digit.
(1) 2,344 $\rightarrow$ 2,340
(2) 2,348 $\rightarrow$ 2,350 (8 $\ge$ 5, round up)
(3) 2,355 $\rightarrow$ 2,360
(4) 2,359 $\rightarrow$ 2,360
Only 2,348 rounds to 2,350.

5. (2)
Reasoning: The pattern increases by 100 each time.
$2,300 + 100 = 2,400$.
Check: $2,400 + 100 = 2,500$. Correct.

6. (2)
Reasoning: Number: 5,050.
Thousands: 5, Hundreds: 0, Tens: 5, Ones: 0.
(1) 5 is not 5 times 5.
(2) Digit in hundreds place is 0. True.
(3) Value of 5 in thousands is 5,000.
(4) Ends in 0, so it is even.

7. (1)
Reasoning: Ascending order means smallest to largest.
Compare thousands: All are 4.
Compare hundreds: 0 (4,021), 1 (4,120, 4,102), 2 (4,210).
Smallest is 4,021.
Next, compare 4,120 and 4,102. Look at tens: 2 vs 0. 4,102 is smaller.
Order: 4,021, 4,102, 4,120, 4,210.

8. (1)
Reasoning: Largest number $\rightarrow$ put largest digits at the front.
Digits: 8, 7, 3, 0.
Start with 8 (Thousands).
Next largest is 7 (Hundreds).
Next is 3 (Tens).
Last is 0 (Ones).
Number: 8,730.
Check if even: Ends in 0, so it is even.
If we tried 8,703, it is odd.
If we tried 8,370, it is smaller than 8,730.

9. (3)
Reasoning: Find the difference from 5,000.
(1) $5,000 - 4,890 = 110$
(2) $5,120 - 5,000 = 120$
(3) $5,000 - 4,950 = 50$
(4) $5,090 - 5,000 = 90$
Smallest difference is 50, so 4,950 is closest.

10. (2)
Reasoning: $7,000 - 6,990 = 10$.
Alternatively, count up from 6,990 to 7,000.

Section B: Short Answer Questions (20 marks)

11. 6,045
Reasoning:
Six thousand = 6,000
Forty-five = 45
No hundreds mentioned = 0
Combine: 6,045.

12. 8,700
Reasoning:
Value of digit 9 (thousands place) = 9,000.
Value of digit 3 (hundreds place) = 300.
Difference: $9,000 - 300 = 8,700$.

13. 2,059
Reasoning:
Smallest number $\rightarrow$ smallest non-zero digit at the front (cannot start with 0).
Available digits: 0, 2, 5, 9.
Thousands: 2 (smallest non-zero).
Remaining: 0, 5, 9.
Hundreds: 0 (smallest available).
Remaining: 5, 9.
Tens: 5.
Ones: 9.
Number: 2,059.
Check if odd: Ends in 9, so it is odd. Correct.

14. 4,600
Reasoning:
Round to nearest hundred. Look at the tens digit (6).
Since $6 \ge 5$, round up the hundreds digit.
$5 + 1 = 6$.
Replace tens and ones with 0.
Result: 4,600.

15. 8,350
Reasoning:
Pattern: $8,500 \rightarrow 8,450$ (subtract 50).
$8,450 \rightarrow 8,400$ (subtract 50).
Next: $8,400 - 50 = 8,350$.
Check: $8,350 - 50 = 8,300$. Correct.

16. 2,902, 2,209, 2,099, 2,029
Reasoning:
Descending order means largest to smallest.
Thousands: All 2.
Hundreds: 9 (2,902), 2 (2,209), 0 (2,099, 2,029).
Largest: 2,902.
Next: 2,209.
Compare 2,099 and 2,029. Look at tens: 9 vs 2.
2,099 is larger than 2,029.
Order: 2,902, 2,209, 2,099, 2,029.

17. 4,695
Reasoning:
3215

• 1480

Ones: $5+0=5$
Tens: $1+8=9$
Hundreds: $2+4=6$
Thousands: $3+1=4$
Result: 4,695.

18. 2,944
Reasoning:
5000

• 2056

Ones: $0-6$ (borrow from tens, but tens is 0, borrow from hundreds, but hundreds is 0, borrow from thousands).
Thousands becomes 4. Hundreds becomes 9. Tens becomes 9. Ones becomes 10.
Ones: $10-6=4$
Tens: $9-5=4$
Hundreds: $9-0=9$
Thousands: $4-2=2$
Result: 2,944.

19. 3,700
Reasoning:
The number line goes from 3,000 to 4,000.
There are 10 intervals.
Value of each interval = $(4,000 - 3,000) / 10 = 100$.
The arrow is at the 7th mark after 3,000.
$3,000 + (7 \times 100) = 3,000 + 700 = 3,700$.

20. 4,700
Reasoning:
Ali = 4,200.
Ben = Ali + 500.
Ben = $4,200 + 500 = 4,700$.

Section C: Long Answer Questions (10 marks)

21. (a) 5,630 (b) 1,270
Reasoning:
(a) Total books = Fiction + Non-fiction
$3,450 + 2,180$
Ones: $0+0=0$
Tens: $5+8=13$ (write 3, carry 1)
Hundreds: $4+1+1(\text{carry})=6$
Thousands: $3+2=5$
Total = 5,630.

(b) Difference = Fiction - Non-fiction
$3,450 - 2,180$
Ones: $0-0=0$
Tens: $5-8$ (borrow from hundreds). $15-8=7$.
Hundreds: $3-1=2$ (4 became 3 after borrowing).
Thousands: $3-2=1$.
Difference = 1,270.

Marking:
(a) 2 marks for correct answer. 1 mark for correct method with minor calculation error.
(b) 3 marks for correct answer. 1 mark for correct method.

22. (a) 950 (b) 2,200
Reasoning:
(a) Sunday tickets = Saturday tickets - 300
$1,250 - 300$
$1,250 - 250 = 1,000$
$1,000 - 50 = 950$.
Or:
1250

• 300

950

(b) Total = Saturday + Sunday
$1,250 + 950$
Ones: $0+0=0$
Tens: $5+5=10$ (write 0, carry 1)
Hundreds: $2+9+1(\text{carry})=12$ (write 2, carry 1)
Thousands: $1+1(\text{carry})=2$
Total = 2,200.

Marking:
(a) 2 marks for correct answer.
(b) 3 marks for correct answer. Must use answer from (a) or correct independent calculation. If (a) is wrong but method for (b) is correct using their wrong (a), award method marks.