Primary 2 Mathematics Length Quiz

Primary 2 Mathematics Quiz - Length: Answer Key

Total Marks: 40

Section A: Multiple Choice Questions (5 × 1 mark = 5 marks)

1. B) Metres (m)

• Answer: B
• Explanation: A classroom is a large space. Metres (m) are used to measure longer lengths like the length of a room. Centimetres (cm) are for smaller objects like pencils. Kilograms (kg) measure mass, and litres (ℓ) measure volume.
• Marking: 1 mark for correct answer.

2. C) A table that is 1 m long

• Answer: C
• Explanation: We need to compare all lengths in the same unit. 1 m is equal to 100 cm. So the table is 100 cm long. Comparing 15 cm, 25 cm, 100 cm, and 8 cm, the table (100 cm) is the longest.
• Marking: 1 mark for correct answer.

3. C) 200 cm

• Answer: C
• Explanation: 1 metre (m) is equal to 100 centimetres (cm). Therefore, 2 metres is equal to 2 × 100 = 200 cm.
• Marking: 1 mark for correct answer.

4. B) A bus

• Answer: B
• Explanation: A bus is a very long object. Metres (m) are used to measure long objects like buses, rooms, or fences. Paper clips, rubber bands, and spoons are small and are measured in centimetres (cm).
• Marking: 1 mark for correct answer.

5. A) 40 cm

• Answer: A
• Explanation: First, convert 1 m to cm: 1 m = 100 cm. Then, subtract the length of the string from the rope: 100 cm − 60 cm = 40 cm. The rope is 40 cm longer.
• Marking: 1 mark for correct answer.

Section B: Short Answer Questions (10 × 2 marks = 20 marks)

6. 8 cm

• Answer: 8
• Explanation: Using a ruler, align the start point of the line with the 0 cm mark. The end point should align with the 8 cm mark. The line is 8 cm long.
• Marking: 2 marks for correct measurement. 1 mark if the measurement is off by 1 cm.

7. (a) 300 cm (b) 1 m 50 cm

• Answers: (a) 300 (b) 1, 50
• Explanation:
  • (a) 1 m = 100 cm, so 3 m = 3 × 100 = 300 cm.
  • (b) 150 cm can be split into 100 cm + 50 cm. 100 cm is equal to 1 m. So, 150 cm is 1 m 50 cm.
• Marking: 1 mark for each correct part.

8. 95 cm, 1 m, 120 cm, 2 m

• Answer: 95 cm, 1 m, 120 cm, 2 m
• Explanation: First, convert all lengths to the same unit (cm). 1 m = 100 cm and 2 m = 200 cm. Now we can compare: 95 cm, 100 cm, 120 cm, 200 cm. The order from shortest to longest is: 95 cm, 1 m, 120 cm, 2 m.
• Marking: 2 marks for the correct order. 1 mark if the order is reversed or has one error.

9. 73 cm

• Answer: 73
• Explanation: To find the total length, we add the two lengths together: 45 cm + 28 cm = 73 cm.
• Marking: 2 marks for correct answer with correct unit. 1 mark for correct method but wrong answer.

10. 85 cm

• Answer: 85
• Explanation: First, convert the snake's length to cm: 1 m 20 cm = 100 cm + 20 cm = 120 cm. Then, subtract the lizard's length: 120 cm − 35 cm = 85 cm. The snake is 85 cm longer.
• Marking: 2 marks for correct answer with correct unit. 1 mark for correct method but wrong answer.

11. 12 cm

• Answer: 12
• Explanation: The paintbrush is aligned with the ruler. It starts at 0 cm and ends at 12 cm. Therefore, its length is 12 cm.
• Marking: 2 marks for correct measurement.

12. 125 cm

• Answer: 125
• Explanation: First, convert the tape length to cm: 2 m = 200 cm. Then, subtract the used amount: 200 cm − 75 cm = 125 cm. There is 125 cm of tape left.
• Marking: 2 marks for correct answer with correct unit. 1 mark for correct method but wrong answer.

13. (a) more than (b) more than

• Answers: (a) more than (b) more than
• Explanation:
  • (a) 1 m is 100 cm. 100 cm is more than 90 cm.
  • (b) 2 m is 200 cm. 250 cm is more than 200 cm.
• Marking: 1 mark for each correct part.

14. 400 cm

• Answer: 400
• Explanation: 1 m = 100 cm. Therefore, 4 m = 4 × 100 = 400 cm.
• Marking: 2 marks for correct answer with correct unit.

15. 30 cm

• Answer: 30
• Explanation: To find the total distance, we add the two distances: 12 cm + 18 cm = 30 cm. The worm moves 30 cm altogether.
• Marking: 2 marks for correct answer with correct unit. 1 mark for correct method but wrong answer.

Section C: Word Problems (3 × 5 marks = 15 marks)

16. 90 cm

• Answer: 90 cm
• Explanation:
  1. Convert the wood's length to cm: 1 m 50 cm = 100 cm + 50 cm = 150 cm.
  2. Subtract the cut-off part: 150 cm − 60 cm = 90 cm.
  3. The length of the wood left is 90 cm.
• Marking:
  • 1 mark for correct conversion (1 m 50 cm = 150 cm).
  • 2 marks for correct subtraction (150 − 60 = 90).
  • 1 mark for correct answer with unit (90 cm).
  • 1 mark for a complete sentence answer.

17. 1 m

• Answer: 1 m
• Explanation:
  1. Convert the ribbon length to cm: 3 m = 300 cm.
  2. Divide the total length by the number of pieces: 300 cm ÷ 3 = 100 cm.
  3. Convert back to metres: 100 cm = 1 m.
  4. Each piece is 1 m long.
• Marking:
  • 1 mark for correct conversion (3 m = 300 cm).
  • 2 marks for correct division (300 ÷ 3 = 100).
  • 1 mark for correct conversion back to metres (100 cm = 1 m).
  • 1 mark for a complete sentence answer.

18. Yes, the chair can fit.

• Answer: Yes, the chair can fit along the length of the table.
• Explanation:
  1. Convert the table's length to cm: 1 m 20 cm = 100 cm + 20 cm = 120 cm.
  2. Compare the table's length (120 cm) with the chair's width (45 cm).
  3. Since 120 cm is greater than 45 cm, the chair can fit along the length of the table.
• Marking:
  • 1 mark for correct conversion (1 m 20 cm = 120 cm).
  • 2 marks for correct comparison (120 cm > 45 cm).
  • 1 mark for correct conclusion (Yes).
  • 1 mark for a clear explanation.

19. 10 tiles

• Answer: 10 tiles
• Explanation:
  1. Convert the path length to cm: 5 m = 500 cm.
  2. Divide the total length of the path by the length of one tile: 500 cm ÷ 50 cm = 10.
  3. 10 tiles are needed to cover the path.
• Marking:
  • 1 mark for correct conversion (5 m = 500 cm).
  • 2 marks for correct division (500 ÷ 50 = 10).
  • 1 mark for correct answer with unit (10 tiles).
  • 1 mark for a complete sentence answer.

20. 4 m 10 cm

• Answer: 4 m 10 cm
• Explanation:
  1. Add the metres: 2 m + 1 m = 3 m.
  2. Add the centimetres: 30 cm + 80 cm = 110 cm.
  3. Convert 110 cm to m and cm: 110 cm = 1 m 10 cm.
  4. Add the metres: 3 m + 1 m 10 cm = 4 m 10 cm.
  5. The total length of the two ropes is 4 m 10 cm.
• Marking:
  • 1 mark for adding the metres correctly (3 m).
  • 1 mark for adding the centimetres correctly (110 cm).
  • 1 mark for converting 110 cm to 1 m 10 cm.
  • 1 mark for the final answer (4 m 10 cm).
  • 1 mark for a complete sentence answer.

End of Answer Key