O Level / IGCSE Mathematics chapter 1: Number MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

147 exam-style questions on Number, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

147 questions · 18 topics · 10 per test

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What chapter 1 covers

Ten Number questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. Which of these has the largest value?

  1. A
    25
  2. B
    52
  3. C
    33
  4. D
    42
Show answer

Answer: A. 25 = 32, 52 = 25, 33 = 27 and 42 = 16. The largest is 25.

2. A = {x : x is an integer, −2 < x ≤ 3}. Find n(A).

  1. A
    5
  2. B
    6
  3. C
    4
  4. D
    3
Show answer

Answer: A. The integers greater than −2 and up to and including 3 are −1, 0, 1, 2, 3, so n(A) = 5. −2 is not included because of the strict <.

3. A bus timetable shows the bus leaving the station at 10:48, reaching the park at 11:36 and the market at 12:15. How long does the bus take from the park to the market?

  1. A
    79 minutes
  2. B
    1 h 27 min
  3. C
    41 minutes
  4. D
    39 minutes
Show answer

Answer: D. 11:36 to 12:00 is 24 minutes and 12:00 to 12:15 is 15 minutes, a total of 39 minutes. 1 h 27 min is the time from the station to the market.

4. Use a calculator to work out (2.4 × 10−3) ÷ (6 × 105).

  1. A
    4 × 10−9
  2. B
    40
  3. C
    4 × 10−2
  4. D
    4 × 102
Show answer

Answer: A. 2.4 ÷ 6 = 0.4 and 10−3 ÷ 105 = 10−8, so the answer is 0.4 × 10−8 = 4 × 10−9. Typing it without brackets divides by 6 and then multiplies by 105, giving 40.

5. Work out (−6) × (−4) + (−18) ÷ 3.

  1. A
    18
  2. B
    30
  3. C
    −30
  4. D
    −18
Show answer

Answer: A. (−6) × (−4) = +24 and (−18) ÷ 3 = −6, so 24 + (−6) = 18. Two negatives multiplied give a positive.

6. Which of these numbers is written in standard form?

  1. A
    72 × 102
  2. B
    7.2 × 10−3
  3. C
    0.72 × 104
  4. D
    7.2 × 53
Show answer

Answer: B. Standard form is A × 10n with 1 ≤ A < 10 and n an integer. 72 and 0.72 are outside that range, and 53 is not a power of 10.

7. A radioactive sample of 800 g halves in mass every 5 years. What is its mass after 20 years?

  1. A
    50 g
  2. B
    100 g
  3. C
    200 g
  4. D
    25 g
Show answer

Answer: A. 20 years is 20 ÷ 5 = 4 half-lives, so the mass is 800 ÷ 24 = 800 ÷ 16 = 50 g. Dividing by 4 instead of 24 gives 200 g.

8. A calculator gives the time for a journey as 3.45 hours. How long is this in hours and minutes?

  1. A
    3 hours 45 minutes
  2. B
    3 hours 4.5 minutes
  3. C
    3 hours 27 minutes
  4. D
    3 hours 54 minutes
Show answer

Answer: C. 0.45 of an hour is 0.45 × 60 = 27 minutes, so 3.45 hours = 3 hours 27 minutes. The digits after the decimal point are not minutes.

9. Express 45 minutes as a percentage of 2 hours.

  1. A
    22.5%
  2. B
    45%
  3. C
    37.5%
  4. D
    2.67%
Show answer

Answer: C. Use the same units: 2 hours = 120 minutes, and 45/120 × 100 = 37.5%. Treating 2 hours as 200 minutes gives 22.5%.

10. Work out 1 2/3 × 2 1/4, giving your answer as a mixed number.

  1. A
    2 1/6
  2. B
    3 3/4
  3. C
    3 11/12
  4. D
    4 1/6
Show answer

Answer: B. Change to improper fractions: 5/3 × 9/4 = 45/12 = 15/4 = 3 3/4. Multiplying the whole numbers and the fractions separately gives 2 1/6, and 3 11/12 is the sum, not the product.

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How many Number MCQs are there?

147, each with the answer and a short explanation, across 18 topics: Types of number, Sets, Powers and roots, Fractions, decimals and percentages, Ordering, The four operations, Indices I, Standard form, Estimation, Limits of accuracy, Ratio and proportion, Rates, Percentages, Using a calculator, Time, Money, Exponential growth and decay, Surds. Every chapter test draws ten of them, so you can take it many times.

Is the O Level / IGCSE Mathematics chapter 1 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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