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O Level & A Level Mathematics (Cambridge)

O Level Mathematics — Number, Set 2

Take the O Level Mathematics — Number, Set 2: 20 multiple-choice questions (30 minutes) with instant scoring and a full answer review. Covers 20 O Level…

What this test covers

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

  1. Q1. What is the highest common factor of 48 and 72?

    • A. 144
    • B. 6
    • C. 24 ✓
    • D. 12

    Answer: C. 24

    Explanation: 48 = 2⁴ × 3 and 72 = 2³ × 3²; HCF = 2³ × 3 = 24.

  2. Q2. What is the lowest common multiple of 8, 12 and 15?

    • A. 120 ✓
    • B. 240
    • C. 1440
    • D. 60

    Answer: A. 120

    Explanation: 8 = 2³, 12 = 2² × 3, 15 = 3 × 5; LCM = 2³ × 3 × 5 = 120.

  3. Q3. Write 6.02 × 10⁻³ as an ordinary number.

    • A. 0.0602
    • B. 0.000602
    • C. 6020
    • D. 0.00602 ✓

    Answer: D. 0.00602

    Explanation: Move the decimal point 3 places left.

  4. Q4. Calculate (4 × 10³) × (5 × 10⁴), giving the answer in standard form.

    • A. 2 × 10⁸ ✓
    • B. 2 × 10⁷
    • C. 20 × 10⁷
    • D. 9 × 10⁷

    Answer: A. 2 × 10⁸

    Explanation: 4 × 5 = 20 and 10³ × 10⁴ = 10⁷, so 20 × 10⁷ = 2 × 10⁸.

  5. Q5. Round 0.0047268 to 2 significant figures.

    • A. 0.0047 ✓
    • B. 0.00
    • C. 0.005
    • D. 0.0048

    Answer: A. 0.0047

    Explanation: The first significant figure is 4; keep 4 and 7 (the next digit, 2, rounds down).

The other 15 questions

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  1. Q6. Calculate 1½ ÷ ¾.

    • A. 3
    • B. 2
    • C. 1/2
    • D. 9/8

  2. Q7. Divide 360 in the ratio 2 : 3 : 4. What is the largest part?

    • A. 180
    • B. 120
    • C. 80
    • D. 160

  3. Q8. Increase 250 by 12%.

    • A. 30
    • B. 280
    • C. 312
    • D. 262

  4. Q9. After a 15% discount, a jacket costs $170. What was the original price?

    • A. $195.50
    • B. $185
    • C. $144.50
    • D. $200

  5. Q10. A $12,000 car loses 10% of its value each year. What is it worth after 2 years?

    • A. $9800
    • B. $9720
    • C. $9600
    • D. $10 800

  6. Q11. Evaluate 5⁰ + 2⁻¹.

    • A. 0.5
    • B. 7
    • C. 1.5
    • D. 1

  7. Q12. Evaluate 16^(3/4).

    • A. 12
    • B. 4
    • C. 8
    • D. 64

  8. Q13. Write 0.2777… (the 7 recurs) as a fraction in its simplest form.

    • A. 25/99
    • B. 277/1000
    • C. 5/19
    • D. 5/18

  9. Q14. A mass is 4.6 kg, correct to 1 decimal place. What is its lower bound?

    • A. 4.55 kg
    • B. 4.59 kg
    • C. 4.65 kg
    • D. 4.5 kg

  10. Q15. Write 252 as a product of prime factors.

    • A. 4 × 63
    • B. 2³ × 3 × 7
    • C. 2² × 3² × 7
    • D. 2 × 3² × 14

  11. Q16. A bus travels 45 km in 40 minutes. What is its average speed in km/h?

    • A. 75 km/h
    • B. 67.5 km/h
    • C. 1.125 km/h
    • D. 60 km/h

  12. Q17. Write 2.4 hours in hours and minutes.

    • A. 2 hours 24 minutes
    • B. 2 hours 4 minutes
    • C. 2 hours 14 minutes
    • D. 2 hours 40 minutes

  13. Q18. $500 earns $60 simple interest in 3 years. What is the annual interest rate?

    • A. 12%
    • B. 3%
    • C. 4%
    • D. 6%

  14. Q19. A map has scale 1 : 25 000. How long on the map is a real distance of 3 km?

    • A. 7.5 cm
    • B. 12 cm
    • C. 120 cm
    • D. 1.2 cm

  15. Q20. A person's mass falls from 80 kg to 68 kg. What is the percentage decrease?

    • A. 17.6%
    • B. 12%
    • C. 85%
    • D. 15%