Primary 4 Mathematics Multiplication Division Quiz

Primary 4 Mathematics Quiz - Multiplication Division: Answer Key

Total Marks: 50 | Version: Practice Quiz 1 of 5

Teaching notes are written for students new to the topic. Key idea: multiplication is repeated equal grouping; division splits a total into equal groups.

Answer 1.

468 [1] Method: $234 \times 2$ means two groups of 234. Multiply the ones, tens, hundreds: $4 \times 2 = 8$, $3 \times 2 = 6$, $2 \times 2 = 4$, giving 468. Common mistake: forgetting to carry when a digit product exceeds 9 (not needed here).

Answer 2.

90 [1] Method: $630 \div 7$ asks "7 groups of what makes 630?" Since $63 \div 7 = 9$, then $630 \div 7 = 90$ (the zero carries over because 630 is 63 tens). Common mistake: writing 9 instead of 90 — always check place value.

Answer 3.

54,000 [1] Method: $9 \times 6 = 54$, then attach the three zeros from 6,000: $9 \times 6{,}000 = 54{,}000$. Marking note: accept 54 000 with any spacing; the three zeros are required.

Answer 4.

7 bags [1] Method: sharing 56 into equal groups of 8 is division: $56 \div 8 = 7$. Check by multiplying back: $7 \times 8 = 56$. ✓

Answer 5.

70 [1] Method: This is a missing-factor question. Think $2{,}800 \div 40$: since $28 \div 4 = 7$, then $2{,}800 \div 40 = 70$. Check: $40 \times 70 = 2{,}800$. ✓ Key idea: multiplication and division are inverse operations.

Answer 6.

16,070 [2] Method (short multiplication, 4-digit × 1-digit):

• Ones: $4 \times 5 = 20$ → write 0, carry 2
• Tens: $1 \times 5 = 5$, plus carry 2 = 7
• Hundreds: $2 \times 5 = 10$ → write 0, carry 1
• Thousands: $3 \times 5 = 15$, plus carry 1 = 16

$3{,}214 \times 5 = 16{,}070$ Marks: [1] correct method/setup, [1] correct final answer. Common mistake: misplacing the carried digit or missing a zero in the answer.

Answer 7.

182 [2] Method (long division):

• $7 \div 4 = 1$ remainder 3
• Bring down 2: $32 \div 4 = 8$ remainder 0
• Bring down 8: $8 \div 4 = 2$ remainder 0

$728 \div 4 = 182$ Check: $182 \times 4 = 728$. ✓ Marks: [1] correct division steps, [1] correct answer.

Answer 8.

5,635 [2] Method (3-digit × 2-digit, split 23 into 20 and 3):

• $245 \times 20 = 4{,}900$
• $245 \times 3 = 735$
• Add: $4{,}900 + 735 = 5{,}635$

Marks: [1] both partial products correct, [1] correct addition/final answer. Common mistake: multiplying by 2 instead of 20 in the first row (misaligned place value).

Answer 9.

Quotient = 763, Remainder = 5 [2] Method (long division of 4,583 by 6):

• $45 \div 6 = 7$ remainder 3
• Bring down 8: $38 \div 6 = 6$ remainder 2
• Bring down 3: $23 \div 6 = 3$ remainder 5

So $4{,}583 = 6 \times 763 + 5$. Check: $763 \times 6 = 4{,}578$; $4{,}578 + 5 = 4{,}583$. ✓ Marks: [1] correct working, [1] both quotient and remainder correct. Common mistake: giving a remainder larger than the divisor (never valid — here remainder must be less than 6).

Answer 10.

$52 \approx 50$ and $29 \approx 30$, so $52 \times 29 \approx 1{,}500$ [2] Method: Round each factor to the nearest ten ($52 \to 50$ since 2 < 5 rounds down; $29 \to 30$ since 9 ≥ 5 rounds up), then multiply: $50 \times 30 = 1{,}500$. Marks: [1] both roundings correct, [1] correct estimate with $\approx$. Note: the exact answer is 1,508, which is close to 1,500 — estimates help us check whether exact answers are reasonable.

Answer 11.

5,760 pages [3] Method: 128 pages each minute, 45 minutes → total $= 128 \times 45$.

• Split 45 into 40 and 5: $128 \times 40 = 5{,}120$
• $128 \times 5 = 640$
• $5{,}120 + 640 = 5{,}760$

Answer: 5,760 pages Marks: [1] choosing $128 \times 45$, [1] correct partial products, [1] correct total with unit. Common mistake: multiplying 128 by 4 instead of 40.

Answer 12.

700 beads [3] Method (two-step problem):

• Step 1: beads left after the bracelet: $3{,}750 - 250 = 3{,}500$
• Step 2: share equally among 5 friends: $3{,}500 \div 5 = 700$

Answer: 700 beads each Marks: [1] subtraction step, [1] division step, [1] correct answer with unit. Common mistake: dividing 3,750 by 5 before subtracting — read carefully for what happens first.

Answer 13.

(a) The four rectangles contain: 600, 180, 80, 24 [1] (b) $34 \times 26 = 884$ [2] Method: The area model splits 34 into $30 + 4$ and 26 into $20 + 6$. Each small rectangle is one pair multiplied:

• $30 \times 20 = 600$
• $30 \times 6 = 180$
• $4 \times 20 = 80$
• $4 \times 6 = 24$

Add all four parts: $600 + 180 + 80 + 24 = 884$. Key idea: this works because of the distributive property — a big multiplication becomes four easier ones. Marks: (a) [1] all four values correct; (b) [1] correct addition of the four parts, [1] final answer 884. Expected visual: the rendered model must show edge labels 30, 4 (top) and 20, 6 (side) with partial products 600, 180, 80, 24 inside the four rectangles.

Answer 14.

(a) 30 full boxes [1] (b) 5 tins left over [1] (c) 3 more tins [1] Method: $245 \div 8 = 30$ remainder $5$, because $30 \times 8 = 240$ and $245 - 240 = 5$. (c) A full box needs 8 tins, so tins still needed $= 8 - 5 = 3$. Marks: [1] each correct part with working shown. Common mistake in (c): answering 5 (the remainder) instead of comparing the remainder to the box size of 8.

Answer 15.

(i) 16.2 [1] (ii) 2.4 [1] (iii) 0.7 [1] Method:

• (i) Ignore the point first: $27 \times 6 = 162$. There is 1 decimal place in 2.7, so put the point one place from the right: $16.2$.
• (ii) $72 \div 3 = 24$; with 1 decimal place in 7.2, the answer is $2.4$.
• (iii) $56 \div 8 = 7$; with 1 decimal place in 5.6, the answer is $0.7$.

Key idea: multiply or divide the digits as whole numbers first, then place the decimal point according to the decimal places in the question. Common mistake: writing 162 instead of 16.2 — count decimal places every time.

Answer 16.

276 cans [4] Method (two-step problem):

• Step 1: total cans bought: $18 \times 24 = 432$
  • ($18 \times 20 = 360$; $18 \times 4 = 72$; $360 + 72 = 432$)
• Step 2: cans not sold: $432 - 156 = 276$

Answer: 276 cans Marks: [1] correct multiplication setup, [1] correct product 432, [1] correct subtraction, [1] correct final answer with unit. Common mistake: subtracting before multiplying, or misreading "not sold" as the amount sold.

Answer 17.

(a) 540 cm [2] (b) 5.4 m [2] Method:

• (a) Cut into 8 equal pieces means divide: $4{,}320 \div 8 = 540$ cm.
  • ($43 \div 8 = 5$ remainder 3; bring down 2 → $32 \div 8 = 4$; bring down 0 → $0 \div 8 = 0$)
• (b) $100$ cm $= 1$ m, so $540 \div 100 = 5.4$ m.

Marks: (a) [1] division setup, [1] correct answer 540 cm; (b) [1] dividing by 100 correctly, [1] answer 5.4 m with unit. Common mistake: writing 5.40 m is acceptable, but 54 m or 0.54 m shows a place-value slip when dividing by 100.

Answer 18.

(a) $42 \times (15 + 5)$ (or $(15 + 5) \times 42$) [2] (b) 840 [2] Method: Both terms share the factor 42. Factorising out 42 gives $42 \times (15 + 5)$.

• Bracket first: $15 + 5 = 20$
• Then $42 \times 20 = 840$

Check the long way: $42 \times 15 = 630$ and $42 \times 5 = 210$; $630 + 210 = 840$. ✓ Key idea: this is the distributive property in reverse — $a \times b + a \times c = a \times (b + c)$. Marks: (a) [1] recognising the common factor 42, [1] correct bracketed form; (b) [1] evaluating the bracket first, [1] correct answer 840.

Answer 19.

7 buses [4] Method:

• Divide: $256 \div 40 = 6$ remainder $16$, since $6 \times 40 = 240$ and $256 - 240 = 16$.
• Interpretation: 6 buses carry 240 pupils, but 16 pupils still have no seat.
• Therefore one extra bus is needed: $6 + 1 = 7$ buses.

Explanation (expected): The remainder cannot be ignored here because every pupil must have a seat, so we always round up to the next whole bus. Marks: [1] correct division with remainder, [1] correct interpretation of the remainder, [1] answer 7 buses, [1] valid explanation about rounding up. Common mistake: answering 6 buses — check whether the remainder people can be left behind!

Answer 20.

29 [4] Method (work backwards, reversing each operation):

• The last operation was "divided by 2", so reverse it by multiplying: $203 \times 2 = 406$.
• Before that, the number was "multiplied by 14", so reverse it by dividing: $406 \div 14 = 29$.

Check forwards: $29 \times 14 = 406$, then $406 \div 2 = 203$. ✓ Marks: [1] reversing division with multiplication, [1] correct value 406, [1] reversing multiplication with division, [1] correct answer 29. Key idea: to undo a chain of operations, reverse them in the opposite order, swapping each operation with its inverse.

End of Answer Key