Primary 3 Mathematics Fractions Quiz

Primary 3 Mathematics Quiz - Fractions

Answer Key

Section A: Understanding Fractions (1 mark each)

1. 1/2

The figure is divided into 4 equal parts. 2 parts are shaded. Fraction = 2/4 = 1/2.

Marking note: Accept 2/4. Award 1 mark for correct answer.

2. (b) 3/6

3/6 = 3 ÷ 3 / 6 ÷ 3 = 1/2.

Marking note: Award 1 mark for the correct option.

3. 3/5

Three-fifths = 3/5 (numerator 3, denominator 5).

Marking note: Award 1 mark for 3/5.

4. Numerator: 5, Denominator: 8

In a fraction, the top number is the numerator and the bottom number is the denominator.

Marking note: Award 1 mark for both correct. 0 marks if only one is correct.

5. 4

One whole = 4/4, so there are 4 quarters in one whole.

Marking note: Award 1 mark for 4.

Section B: Equivalent Fractions (2 marks each)

6. 3

1/3 = ___/9. To get from 3 to 9, multiply by 3. So multiply the numerator by 3: 1 × 3 = 3.

1/3 = 3/9.

Marking note: Award 2 marks for correct answer with working. Award 1 mark for correct answer only.

7. 20

2/5 = 8/___. To get from 2 to 8, multiply by 4. So multiply the denominator by 4: 5 × 4 = 20.

2/5 = 8/20.

Marking note: Award 2 marks for correct answer with working. Award 1 mark for correct answer only.

8. 6/8 and 9/12 (other correct answers accepted, e.g., 12/16, 15/20)

Multiply numerator and denominator by the same number:

• 3/4 × 2/2 = 6/8
• 3/4 × 3/3 = 9/12

Marking note: Award 2 marks for two correct equivalent fractions. Award 1 mark for one correct equivalent fraction.

9. 1/2 = 2/4 = 3/6 = 4/8

Multiply numerator and denominator by the same number each time:

• 1/2 × 2/2 = 2/4
• 1/2 × 3/3 = 3/6
• 1/2 × 4/4 = 4/8

Marking note: Award 2 marks for all three correct. Award 1 mark for two correct.

10. (d) 6/10

Check each:

• 4/6 = 4÷2/6÷2 = 2/3 ✓
• 6/9 = 6÷3/9÷3 = 2/3 ✓
• 8/12 = 8÷4/12÷4 = 2/3 ✓
• 6/10 = 6÷2/10÷2 = 3/5 ≠ 2/3 ✗

Marking note: Award 2 marks for correct answer with working. Award 1 mark for correct option only.

Section C: Comparing and Ordering Fractions (2 marks each)

11. <

3/8 < 5/8. When denominators are the same, compare numerators. 3 < 5, so 3/8 < 5/8.

Marking note: Award 2 marks for correct symbol with explanation. Award 1 mark for correct symbol only.

12. >

2/3 > 2/5. When numerators are the same, the fraction with the smaller denominator is larger. 3 < 5, so 2/3 > 2/5.

Marking note: Award 2 marks for correct symbol with explanation. Award 1 mark for correct symbol only.

13. 1/8, 1/6, 1/4, 1/2

All fractions have the same numerator (1). The larger the denominator, the smaller the fraction. Order of denominators: 8 > 6 > 4 > 2, so order of fractions: 1/8 < 1/6 < 1/4 < 1/2.

Marking note: Award 2 marks for all four in correct order. Award 1 mark for at least two in correct relative position.

14. 4/7 is greater.

Both fractions have the same denominator (7). Compare numerators: 4 > 3, so 4/7 > 3/7.

Marking note: Award 2 marks for correct answer with explanation. Award 1 mark for correct answer only.

15. Raj ate more. He ate 1/6 more than Meena.

Raj ate 3/6, Meena ate 2/6. Since 3/6 > 2/6, Raj ate more. Difference: 3/6 − 2/6 = 1/6.

Marking note: Award 2 marks for correct answer with working. Award 1 mark for identifying who ate more without the difference.

Section D: Adding and Subtracting Fractions (3 marks each)

16. 5/7

2/7 + 3/7 = (2+3)/7 = 5/7.

When adding fractions with the same denominator, add the numerators and keep the denominator.

Marking note: Award 3 marks for correct answer with working. Award 2 marks for correct answer only. Award 1 mark for correct method with arithmetic error.

17. 3/6 (or 1/2 in simplest form)

5/6 − 2/6 = (5−2)/6 = 3/6 = 1/2.

Marking note: Award 3 marks for correct answer in simplest form with working. Award 2 marks for 3/6 with working. Award 1 mark for correct method with arithmetic error.

18. 3/4

1/4 + 2/4 = (1+2)/4 = 3/4.

3/4 is already in its simplest form.

Marking note: Award 3 marks for correct answer with working. Award 2 marks for correct answer only. Award 1 mark for correct method with arithmetic error.

19. 4/10 = 2/5

7/10 − 3/10 = (7−3)/10 = 4/10 = 2/5.

Marking note: Award 3 marks for correct answer in simplest form with working. Award 2 marks for 4/10 with working. Award 1 mark for correct method with arithmetic error.

20.

(a) 5/8

Siti ate 3/8, brother ate 2/8. Total eaten: 3/8 + 2/8 = (3+2)/8 = 5/8.

(b) 3/8

Fraction left: 1 − 5/8 = 8/8 − 5/8 = 3/8.

Marking note: Award 3 marks for both parts correct with working. Award 2 marks for one part correct with working, or both answers correct without working. Award 1 mark for correct method in either part.

Summary of Marks