Primary 5 Mathematics Semestral Assessment 2 (End of Year) Paper 4

TuitionGoWhere Exam Practice (AI) - Mathematics Primary 5 Answer Key

Paper: SA2 Practice Paper (Version 4 of 5)
Total Marks: 100

Section A (20 marks)

1. 8,045,006 [1]
Teaching Note: Break down the words: "Eight million" = 8,000,000. "Forty-five thousand" = 45,000. "Six" = 6. Combine them: 8,000,000 + 45,000 + 6 = 8,045,006. Ensure zeros are placed correctly in the hundred-thousands, ten-thousands, hundreds, and tens columns.

2. 700,000 (or Seven hundred thousand) [1]
Teaching Note: Identify the place value. The digit 7 is in the hundred-thousands place. Value = $7 \times 100,000 = 700,000$.

3. 5,700,000 [1]
Teaching Note: To round to the nearest hundred thousand, look at the ten-thousands digit (7). Since $7 \ge 5$, round up the hundred-thousands digit (6 becomes 7). Replace subsequent digits with zeros.

4. 3,045,100; 3,054,100; 3,405,100; 3,450,100 [1]
Teaching Note: Compare digits from left to right. All start with 3 million. Compare hundred-thousands: 0 vs 4. The two starting with 3,0... are smaller. Between 3,045,100 and 3,054,100, compare ten-thousands: 4 < 5. So 3,045,100 is smallest.

5. 45,000 [1]
Teaching Note: Multiplying by 1000 adds three zeros to the end of the whole number.

6. 720 [1]
Teaching Note: Dividing by 100 removes two zeros from the end of the number. $72,000 \div 100 = 720$.

7. 52 [1]
Teaching Note: Follow BODMAS/BIDMAS. Multiplication before addition. $8 \times 5 = 40$. Then $12 + 40 = 52$.

8. 70 [1]
Teaching Note: Brackets first: $(20 - 5) = 15$. Then multiplication: $15 \times 4 = 60$. Then addition: $60 + 10 = 70$.

9. (b) [1]
Teaching Note: Use the distributive property. $36 \times 99 = 36 \times (100 - 1) = 36 \times 100 - 36 \times 1 = 36 \times 100 - 36$.

10. 560,000 [1]
Teaching Note: Subtract February's production from January's: $2,450,000 - 1,890,000$.

11. 10,488 [2]
Teaching Note: Perform standard multiplication.

12. 338 [2]
Teaching Note: Perform long division. $8450 \div 25$. $84 \div 25 = 3$ rem 9. Bring down 5 $\rightarrow$ 95. $95 \div 25 = 3$ rem 20. Bring down 0 $\rightarrow$ 200. $200 \div 25 = 8$. Answer: 338.

13. 60 [2]
Teaching Note: Order of operations: Multiplication first. $25 \times 4 = 100$. Expression becomes $150 - 100 + 10$. Left to right: $150 - 100 = 50$. $50 + 10 = 60$.

14. 20 bags [2]
Teaching Note: Step 1: Find total apples. $5 \times 24 = 120$ apples. Step 2: Divide into bags. $120 \div 6 = 20$ bags.

15. 2,222,222 [2]
Teaching Note: Subtract the difference from City A's population.

Section B (40 marks)

16.
(a) 6,900 books
(b) 5,175 books [4]
Teaching Note:
(a) Total books = Fiction + Non-fiction = $4,560 + 2,340 = 6,900$.
(b) If $\frac{1}{4}$ are borrowed, then $\frac{3}{4}$ are left.
Method 1: Find borrowed first. $\frac{1}{4} \times 6,900 = 1,725$. Left = $6,900 - 1,725 = 5,175$.
Method 2: Find fraction left. $1 - \frac{1}{4} = \frac{3}{4}$. $\frac{3}{4} \times 6,900 = 3 \times 1,725 = 5,175$.

17. 35 [4]
Teaching Note: Follow BODMAS strictly.
Step 1: Brackets. $(8 + 4) = 12$.
Expression: $120 \div 12 \times 5 - 15$.
Step 2: Division and Multiplication (Left to Right).
$120 \div 12 = 10$.
Expression: $10 \times 5 - 15$.
$10 \times 5 = 50$.
Step 3: Subtraction.
$50 - 15 = 35$.

18.
(a) **\9,250$** (b) **Profit of$$3,250$** [4] *Teaching Note:* (a) Cost Price (CP) total =$500 \times 12 = $6,000$. Sales from first 350 shirts:$350 \times 20 = $7,000$. Remaining shirts:$500 - 350 = 150$shirts. Sales from remaining:$150 \times 15 = $2,250$. Total Sales =$7,000 + 2,250 = $9,250$. (b) Profit = Total Sales - Total CP. Profit =$9,250 - 6,000 = $3,250$.
Since Sales > CP, it is a profit.

19.
(a) 3,600 red beads
(b) 3,600 green beads [4]
Teaching Note:
Total beads = 8,400.
(a) Red beads = $\frac{3}{7} \times 8,400$.
$8,400 \div 7 = 1,200$.
$1,200 \times 3 = 3,600$ red beads.
(b) Remainder = $8,400 - 3,600 = 4,800$ beads.
Blue beads = $\frac{1}{4}$ of remainder = $\frac{1}{4} \times 4,800 = 1,200$ blue beads.
Green beads = Remainder - Blue beads = $4,800 - 1,200 = 3,600$ green beads.
Alternative: Green is $\frac{3}{4}$ of remainder. $\frac{3}{4} \times 4,800 = 3,600$.

20.
(a) 1,600 $cm^2$
(b) 300 tiles [4]
Teaching Note:
(a) Area of square tile = side $\times$ side = $40 \text{ cm} \times 40 \text{ cm} = 1,600 \text{ cm}^2$.
(b) Convert floor area to $cm^2$. $1 \text{ m}^2 = 10,000 \text{ cm}^2$.
Floor area = $48 \times 10,000 = 480,000 \text{ cm}^2$.
Number of tiles = Total Area $\div$ Area of one tile.
$480,000 \div 1,600 = 4,800 \div 16 = 300$ tiles.

21.
(a) $10 \times 11 + 10$
(b) 120 [4]
Teaching Note:
Observe the pattern: Pattern $n$ is $n \times (n+1) + n$.
(a) For Pattern 10, $n=10$. Expression: $10 \times 11 + 10$.
(b) Calculate: $10 \times 11 = 110$. $110 + 10 = 120$.

22.
(a) 1,800 seats
(b) 1,800 seats [4]
Teaching Note:
Total seats = 4,500.
(a) Adults = $\frac{2}{5} \times 4,500$.
$4,500 \div 5 = 900$.
$900 \times 2 = 1,800$ adults.
(b) Remainder = $4,500 - 1,800 = 2,700$ seats.
Children = $\frac{1}{3}$ of remainder = $\frac{1}{3} \times 2,700 = 900$ children.
Empty seats = Remainder - Children = $2,700 - 900 = 1,800$ seats.

23. 456,700 [4]
Teaching Note: Use distributive property to simplify.
$4567 \times 101 - 4567$
$= 4567 \times 101 - 4567 \times 1$
$= 4567 \times (101 - 1)$
$= 4567 \times 100$
$= 456,700$.

24.
(a) 40 marbles
(b) 60 marbles
(c) 200 marbles [4]
Teaching Note:
Box A = 120.
(a) Box A = $3 \times$ Box B.
$120 = 3 \times$ Box B.
Box B = $120 \div 3 = 40$ marbles.
(b) Box C = Box B + 20.
Box C = $40 + 20 = 60$ marbles.
(c) Total = A + B + C = $120 + 40 + 60 = 200$ marbles.

25.
(a) 24 pages per minute
(b) 1,440 pages [4]
Teaching Note:
(a) Rate = Total pages $\div$ Time.
$120 \div 5 = 24$ pages/min.
(b) 1 hour = 60 minutes.
Total pages = Rate $\times$ Time.
$24 \times 60 = 1,440$ pages.

Section C (40 marks)

26.
(a) **\200$** (b) **$$75$** (c) **$$225$** [8] *Teaching Note:* Total money =$$500$. (a) Dress cost =$\frac{2}{5} \times 500$.$500 \div 5 = 100$.$100 \times 2 = $200$. (b) Remainder after dress =$500 - 200 = $300$. Shoes cost =$\frac{1}{4}$of remainder =$\frac{1}{4} \times 300$.$300 \div 4 = $75$. (c) Money left = Remainder - Shoes cost.$300 - 75 = $225$. *Check:*$200 + 75 + 225 = 500$. Correct.

27.
(a) 96 medium boxes
(b) 1,440 small packets
(c) 360 kg [8]
Teaching Note:
(a) Medium boxes = Large crates $\times$ boxes per crate.
$12 \times 8 = 96$ medium boxes.
(b) Small packets = Medium boxes $\times$ packets per box.
$96 \times 15$.
$96 \times 10 = 960$.
$96 \times 5 = 480$.
$960 + 480 = 1,440$ small packets.
(c) Total weight in grams = $1,440 \times 250$ g.
$1,440 \times 250 = 360,000$ g.
Convert to kg: $1 \text{ kg} = 1,000 \text{ g}$.
$360,000 \div 1,000 = 360$ kg.

28.
Visual Reference: Stack of cubes: Base 3x3 (9), Middle 2x2 (4), Top 1x1 (1). Side length 5 cm.
(a) 14 cubes
(b) 125 $cm^3$
(c) 1,750 $cm^3$
(d) 33 faces [8]
Teaching Note:
(a) Count cubes: $9 + 4 + 1 = 14$ cubes.
(b) Volume of one cube = $5 \times 5 \times 5 = 125 \text{ cm}^3$.
(c) Total volume = $14 \times 125$.
$10 \times 125 = 1,250$.
$4 \times 125 = 500$.
$1,250 + 500 = 1,750 \text{ cm}^3$.
(d) Painted faces (excluding bottom):

• Top view: 9 faces (area of base).
• Bottom view: 0 (on table).
• Side views (Front, Back, Left, Right):
  Each side view shows a "staircase" profile.
  Front view: 3 (base) + 2 (middle) + 1 (top) = 6 faces.
  Back view: 6 faces.
  Left view: 6 faces.
  Right view: 6 faces.
  Total side faces = $6 \times 4 = 24$.
• Total painted faces = Top (9) + Sides (24) = 33 faces.
  Alternative Counting:
  Total faces of 14 cubes = $14 \times 6 = 84$.
  Subtract hidden/touching faces.
  This method is complex; counting exposed faces by view is safer.
  Top: 9.
  Front: 6. Back: 6. Left: 6. Right: 6.
  Sum: $9 + 24 = 33$.

29.
(a) 120 packs
(b) **\14,400$** (c) **200 packs** (d) **$$26,400$** [8] *Teaching Note:* Participants = 2,400. (a) T-shirts: 1 per participant. Need 2,400 shirts. Packs of 20.$2,400 \div 20 = 120$packs. (b) Cost of T-shirts:$120 \text{ packs} \times $120/\text{pack}$.$12 \times 12 = 144$. Add two zeros:$$14,400$. (c) Water bottles: 1 per participant. Need 2,400 bottles. Packs of 12.$2,400 \div 12 = 200$packs. (d) Cost of bottles:$200 \text{ packs} \times $60/\text{pack}$.$200 \times 60 = $12,000$. Total cost = Cost of T-shirts + Cost of bottles.$14,400 + 12,000 = $26,400$.

30.
(a) 8,000 visitors
(b) 1,400 visitors
(c) 2,520 visitors
(d) 1,753.33 visitors (or $1,753 \frac{1}{3}$) [8]
Teaching Note:
Days: Mon, Tue, Wed, Thu, Fri (5 days). Average = 1,600.
(a) Total for 5 days = Average $\times$ Number of days.
$1,600 \times 5 = 8,000$ visitors.
(b) Sum of known days = $1,200 + 1,500 + 1,800 + 2,100$.
$1,200 + 1,500 = 2,700$.
$1,800 + 2,100 = 3,900$.
$2,700 + 3,900 = 6,600$.
Wed = Total - Sum of known.
$8,000 - 6,600 = 1,400$ visitors.
(c) Friday = 2,100.
Saturday = 20% more than Friday.
20% of 2,100 = $0.2 \times 2,100 = 420$.
Saturday = $2,100 + 420 = 2,520$ visitors.
(d) Total for 6 days (Mon-Sat) = Total (5 days) + Saturday.
$8,000 + 2,520 = 10,520$.
Average = $10,520 \div 6$.
$10,520 \div 6 = 1,753.333...$
Answer: 1,753.33 (to 2 decimal places).