Primary 5 Mathematics Multiplication Division Quiz

Answer Key - Primary 5 Mathematics Quiz - Multiplication Division

Total Marks: 50

Answer 1.

Answer: 4630 (2 marks)

• Multiplying by 100 moves the decimal point 2 places right: $46.3 \rightarrow 463 \rightarrow 4630$.
• Teaching note: The digits never change order; only the decimal point moves. Zeros fill empty places.
• Common mistake: Writing 46.300 — that equals 46.3, unchanged.

Answer 2.

Answer: 90 (2 marks)

• Step 1: $63\,000 \div 100 = 630$ (remove one zero pair).
• Step 2: $630 \div 7 = 90$.
• Teaching note: Dividing by a multiple of 10 means dividing by the power of 10 first, then by the basic fact ($63 \div 7 = 9$, adjusted by zeros).

Answer 3.

Answer: 24 (2 marks)

• Order of operations: division comes before subtraction.
• Step 1: $18 \div 3 = 6$. Step 2: $30 - 6 = 24$.
• Common mistake: $(30 - 18) \div 3 = 4$ — wrong because there are no brackets.

Answer 4.

Answer: 15 (2 marks)

• A missing factor is found by division: $255 \div 17 = 15$.
• Check: $17 \times 15 = 255$. ✓
• Teaching note: Multiplication and division are inverse operations.

Answer 5.

Answer: 108 (2 marks)

• Split: $800 \div 8 = 100$ and $64 \div 8 = 8$; then $100 + 8 = 108$.
• Check: $108 \times 8 = 864$. ✓

Answer 6.

Answer: 34 (2 marks)

• Brackets first: $2 \times 3 = 6$.
• Then division and multiplication left to right: $36 \div 6 = 6$; $7 \times 4 = 28$.
• Finally addition: $6 + 28 = 34$.
• Marking: M1 correct order shown, A1 answer 34.

Answer 7.

**Answer: 10 9

<stage3_quiz_answers_md>

Answer Key - Primary 5 Mathematics Quiz - Multiplication Division

Total Marks: 50

Answer 1.

Answer: 4630 (2 marks)

• Multiplying by 100 moves the decimal point 2 places right: $46.3 \rightarrow 463 \rightarrow 4630$.
• Common mistake: Writing 46.300 — that equals 46.3, unchanged.

Answer 2.

Answer: 90 (2 marks)

• Step 1: $63\,000 \div 100 = 630$. Step 2: $630 \div 7 = 90$.
• Teaching note: Divide by the power of 10 first, then use the basic fact $63 \div 7 = 9$.

Answer 3.

Answer: 24 (2 marks)

• Division before subtraction: $18 \div 3 = 6$; then $30 - 6 = 24$.
• Common mistake: $(30 - 18) \div 3 = 4$ — wrong because there are no brackets.

Answer 4.

Answer: 15 (2 marks)

• Missing factor found by division: $255 \div 17 = 15$.
• Check: $17 \times 15 = 255$. ✓

Answer 5.

Answer: 108 (2 marks)

• Split: $800 \div 8 = 100$ and $64 \div 8 = 8$; then $100 + 8 = 108$.
• Check: $108 \times 8 = 864$. ✓

Answer 6.

Answer: 34 (2 marks)

• Brackets first: $2 \times 3 = 6$.
• Then left to right: $36 \div 6 = 6$; $7 \times 4 = 28$.
• Add: $6 + 28 = 34$.
• Marking: M1 correct order shown, A1 answer 34.

Answer 7.

Answer: 10 948 (2 marks)

• Step 1: $238 \times 40 = 9520$.
• Step 2: $238 \times 6 = 1428$.
• Add: $9520 + 1428 = 10\,948$.
• Marking: M1 correct partial products, A1 final answer.

Answer 8.

Answer: 483 (2 marks)

• Long division: $5796 \div 12$: $57 \div 12 = 4$ r 9; bring down 9 → $99 \div 12 = 8$ r 3; bring down 6 → $36 \div 12 = 3$.
• Check: $483 \times 12 = 5796$. ✓

Answer 9.

Answer: 1224 (2 marks)

• Multiply by 3 first: $4.08 \times 3 = 12.24$.
• Then multiply by 100: $12.24 \rightarrow 1224$.
• Teaching note: $300 = 3 \times 100$, so split the multiplication into two easy steps.

Answer 10.

(a) 34 (b) 19 040 (2 marks)

• (a) Since $56 \times 34 = 1904$, dividing gives back a factor: $1904 \div 56 = 34$.
• (b) $560 = 56 \times 10$, so $560 \times 34 = 1904 \times 10 = 19\,040$.
• Marking: A1 for each part; method credit if relationship explained.

Answer 11.

Answer: $20 (3 marks)

• Step 1: Cost of 1 notebook: \12.50 \div 5 = $2.50$.
• Step 2: Cost of 8 notebooks: \2.50 \times 8 = $20$.
• Marking: M1 unit cost, M1 multiply by 8, A1 answer with units.
• Common mistake: Multiplying $12.50 by 8 directly without finding the unit price.

Answer 12.

Answer: 9310 tins (3 marks)

• Step 1: $245 \times 30 = 7350$.
• Step 2: $245 \times 8 = 1960$.
• Add: $7350 + 1960 = 9310$.
• Marking: M1 correct setup, M1 correct partial products, A1 answer with units.

Answer 13.

Answer: 7 loaves (3 marks)

• Step 1: $1250 \div 175 = 7$ remainder $35$.
• Check: $175 \times 7 = 1225$; $1250 - 1225 = 35$ g left over.
• The remainder is not enough for another loaf, so he can bake 7 loaves.
• Marking: M1 division attempted, A1 quotient 7, A1 explanation that remainder is insufficient.
• Common mistake: Rounding up to 8 — there is not enough flour.

Answer 14.

Answer: 90 pupils (3 marks)

• Step 1: Find one part: $240 \div 8 = 30$.
• Step 2: Take 3 parts: $30 \times 3 = 90$.
• Marking: M1 divide by denominator, M1 multiply by numerator, A1 answer with units.
• Alternative: $\frac{3}{8} \times 240 = \frac{720}{8} = 90$.

Answer 15.

Answer: 23 pieces (3 marks)

• Step 1: Convert units: $4.6 \text{ m} = 460 \text{ cm}$.
• Step 2: $460 \div 20 = 23$.
• Marking: M1 correct conversion, M1 division, A1 answer.
• Common mistake: Dividing 4.6 by 20 without converting units.

Answer 16.

Answer: 70 books (3 marks)

• Step 1: Money from pens: 145 \times \3 = $435$.
• Step 2: Money from books: \995 - $435 = $560$.
• Step 3: Number of books: \560 \div $8 = 70$.
• Marking: M1 pen money, M1 subtraction, A1 division answer.
• Check: $435 + (70 \times 8) = 435 + 560 = 995$. ✓

Answer 17.

Answer: 588 stamps (3 marks)

• Step 1: Stamps in that album at first: $132 + 15 = 147$.
• Step 2: Total stamps: $147 \times 4 = 588$.
• Marking: M1 reverse the giving-away step, M1 multiply by 4 albums, A1 answer.
• Common mistake: Subtracting 15 instead of adding it back.

Answer 18.

(a) 15 km (b) 480 km (3 marks)

• (a) Distance on 1 litre: $315 \div 21 = 15$ km.
• (b) Distance on 32 litres: $15 \times 32 = 480$ km.
• Marking: A1 for (a); M1 setup for (b), A1 answer 480 km.
• Check for (b): $15 \times 32 = 15 \times 30 + 15 \times 2 = 450 + 30 = 480$. ✓

Answer 19.

Answer: First seven numbers: 4, 12, 36, 108, 324, 972, 2916; the 7th number is 2916 (3 marks)

• Each term is multiplied by 3:
• $4 \times 3 = 12$; $12 \times 3 = 36$; $36 \times 3 = 108$; $108 \times 3 = 324$; $324 \times 3 = 972$; $972 \times 3 = 2916$.
• Marking: M1 pattern continued correctly, A1 full list, A1 correct 7th term identified.
• Common mistake: Adding 3 instead of multiplying by 3.

Answer 20.

Answer: 9 bags (3 marks)

• Step 1: Total mangoes: $6 \times 18 = 108$.
• Step 2: Mangoes kept: $108 \div 4 = 27$.
• Step 3: Mangoes packed: $108 - 27 = 81$.
• Step 4: Number of bags: $81 \div 9 = 9$.
• Marking: M1 total mangoes, M1 fraction steps (kept/rest), A1 bags answer.
• Common mistake: Packing the 27 kept mangoes as well, getting 12 bags.

— End of Answer Key —