Primary 4 Mathematics · Chapter 3 · Answers and explanations
Lesson 3.6: Word Problems (answers)
Section A · Multiple choice 4 marks
1. Each box holds 450 sheets of paper. How many sheets are in 6 boxes?1 mark
(A) 456(B) 270(C) 2,700(D) 27,000
Answer: (C) 2,7006 equal boxes, so multiply. 450 × 6: 45 × 6 = 270, then add the zero: 2,700. There are 2,700 sheets.
2. Mei has 235 stamps. Ravi has 4 times as many stamps as Mei. How many stamps does Ravi have?1 mark
(A) 239(B) 705(C) 59(D) 940
Answer: (D) 940Ravi has 4 units and each unit is 235. 235 × 4 = 940. Ravi has 940 stamps. (Do not add: "4 times as many" means multiply.)
3. Siti has $850. Mei has $395. How much more money does Siti have than Mei?1 mark
(A) $455(B) $1,245(C) $555(D) $465
Answer: (A) $455To find how much more, subtract. $850 − $395 = $455. Siti has $455 more.
4. Ali and Ben have 120 cards altogether. Ben has 30 more cards than Ali. How many cards does Ali have?1 mark
(A) 75(B) 45(C) 90(D) 60
Answer: (B) 45Take away the 30 extra: 120 − 30 = 90. Two equal units make 90, so 1 unit = 90 ÷ 2 = 45. Ali has 45 cards. (Ben has 75.)
Section B · Write your answer 11 marks
5. Priya shares 1,848 beads equally among 6 children. How many beads does each child get?1 mark
Answer: 308 beadsEqual sharing, so divide. 1 is smaller than 6, so use the next digit too. 18 ÷ 6 = 3. Bring down 4 to make 4. 4 ÷ 6 = 0 r 4 (write 0). Bring down 8 to make 48. 48 ÷ 6 = 8. So 1,848 ÷ 6 = 308. Each child gets 308 beads.
6. Tank A has 1,350 litres of water. Tank B has 3 times as much water as Tank A. How many litres of water does Tank B have?1 mark
Answer: 4,050 litresTank B has 3 units of 1,350. 1,350 × 3 = 4,050. Tank B has 4,050 litres.
7. Class 4A recycles 2,365 kg of paper. Class 4B recycles 1,978 kg. How many kg more does Class 4A recycle than Class 4B?1 mark
Answer: 387 kgSubtract to find the difference. 2,365 − 1,978 = 387. Class 4A recycles 387 kg more.
8. Ali has 5 times as many stamps as Mei. Ali has 1,265 stamps. How many stamps does Mei have?1 mark
Answer: 253 stampsAli has 5 units, so 1 unit = 1,265 ÷ 5 = 253. Mei has 253 stamps.
9. Two ribbons are 90 cm long altogether. The long ribbon is 12 cm longer than the short ribbon. How long is the long ribbon?1 mark
Answer: 51 cmTake away the 12 cm extra: 90 − 12 = 78. Two equal units make 78, so 1 unit = 78 ÷ 2 = 39 cm. This is the short ribbon. Long ribbon: 39 + 12 = 51 cm.
10. Ravi has 5 times as many marbles as Siti. They have 1,260 marbles altogether. How many more marbles does Ravi have than Siti?2 marks
Answer: 840 marblesSiti has 1 unit and Ravi has 5 units, so there are 6 units in all. 1 unit = 1,260 ÷ 6 = 210. Ravi has 4 more units than Siti: 4 × 210 = 840 marbles.
11. Mei and Ali have $356 altogether. Ali has $48 more than Mei. How much money does Ali have?2 marks
Answer: $202Take away the $48 extra: $356 − $48 = $308. Two equal units make $308, so 1 unit = $308 ÷ 2 = $154. This is Mei's money. Ali: $154 + $48 = $202.
12. A school buys 24 boxes of markers with 12 markers in each box. 72 markers are given to Primary 3. The rest are shared equally among 8 classes. How many markers does each class get?2 marks