N14 Estimation and checking calculations by approximation Quiz: AQA Maths, Unit 1

The 20 questions

1. Estimate 48.7 × 19.6 by rounding each number to 1 significant figure.

   • about 900
   • about 10 000
   • about 1000
   • about 100

2. Estimate 396 ÷ 0.49 by rounding to 1 significant figure.

   • about 800
   • about 400
   • about 80
   • about 8000

3. Estimate the value of (3.9)² + 5.1.

   • about 20
   • about 9
   • about 40
   • about 11

4. Estimate 0.0492 × 812.

   • about 0.4
   • about 400
   • about 40
   • about 4

5. A student says 3.2 × 31 = 99.2. Which estimate shows whether this is reasonable?

   • Wrong, the answer should be about 0.99
   • Reasonable, since 3 × 30 = 90 is close to 99.2
   • Wrong, the answer should be about 9.92
   • Wrong, the answer should be about 990

6. Estimate 5812 ÷ 29.

   • about 2000
   • about 200
   • about 20
   • about 400

7. Estimate the value of 7.8 × 0.49 ÷ 3.9.

   • about 1
   • about 0.1
   • about 4
   • about 10

8. Which is the best estimate for 2 3/4 × 5 7/8?

   • about 2
   • about 30
   • about 18
   • about 10

9. Estimate 1.9% of 4987.

   • about 50
   • about 10
   • about 1000
   • about 100

10. Estimate the total cost of 19 items at £4.85 each.

    • about £50
    • about £1000
    • about £10
    • about £100

11. Estimate the value of √80.

    • about 40
    • about 4
    • about 80
    • about 9

12. Estimate 0.0683 × 51 by rounding to 1 significant figure.

    • about 3.5
    • about 35
    • about 3
    • about 0.35

13. Which calculation checks that 4.9 × 19.8 is about 97?

    • 6 × 30 = 180
    • 5 × 20 = 100, close to 97
    • 4 × 19 = 76
    • 5 × 2 = 10, far from 97

14. Round 34 857 to 2 significant figures.

    • 34 000
    • 35 000
    • 34 900
    • 30 000

15. Estimate 7.9 ÷ 0.21.

    • about 40
    • about 0.4
    • about 4
    • about 400

16. Estimate 2/3 of 29.8.

    • about 20
    • about 2
    • about 15
    • about 200

17. Estimate 13.6².

    • about 2000
    • about 200
    • about 20
    • about 140

18. Estimate the value of (0.31 × 58.9) ÷ 0.19.

    • about 90
    • about 9
    • about 30
    • about 900

19. A student claims 5.9 × 21 is about 120. Which reason best supports this check?

    • No, the answer is about 1200
    • No, the answer is about 1.2
    • No, the answer is about 12
    • Yes, 6 × 20 = 120 is close

20. Estimate 61.8 ÷ 0.31 by rounding to 1 significant figure.

    • about 20
    • about 200
    • about 50
    • about 2000

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