Exam questions · Maths · Calculator Skills
Using Your Calculator
- 6 exam questions
- 16 marks
- 9 quick checks
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1 Work out [2 marks]
Work out \(\dfrac{5.6 + 3.2}{4.1 - 1.7}\). Give your answer correct to 3 significant figures. (2 marks)
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Model answer
\(\dfrac{8.8}{2.4} = 3.666\ldots = 3.67\) to 3 significant figures.
Mark scheme
- \(8.8\) and \(2.4\), or \(3.666\ldots\) — M1
- \(3.67\) — A1
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2 Work out [3 marks]
Hana invests \(\pounds 1500\) for 4 years at 3% per year compound interest. Work out the total value of her investment at the end of 4 years. (3 marks)
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Model answer
\(1500 \times 1.03^4 = \pounds 1688.26\) to the nearest penny.
Mark scheme
- \(1.03^4\) or \(1500 \times 1.03\) repeated — M1
- \(1500 \times 1.03^4\) — M1
- \(1688.26\) — A1
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3 Work out [2 marks]
Work out \((3.2 \times 10^5) \times (4.5 \times 10^{-3})\). Give your answer in standard form. (2 marks)
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Model answer
\(3.2 \times 10^5 \times 4.5 \times 10^{-3} = 1440 = 1.44 \times 10^3\).
Mark scheme
- \(1440\) — M1
- \(1.44 \times 10^3\) — A1
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4 Work out [3 marks]
\(ABC\) is a right-angled triangle with the right angle at \(B\). \(AB = 12\) cm and \(BC = 7\) cm. Work out the size of angle \(BAC\). Give your answer correct to 1 decimal place. (3 marks)
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Model answer
\(\tan BAC = \dfrac{7}{12}\), so angle \(BAC = \tan^{-1}\left(\dfrac{7}{12}\right) = 30.3^\circ\).
Mark scheme
- \(\tan BAC = \dfrac{7}{12}\) — M1
- \(30.256\ldots\) — A1
- \(30.3\) — A1
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5 Work out [3 marks]
Work out \(\sqrt{8.4^2 + 5.1^2}\). Give your answer correct to 3 significant figures. (3 marks)
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Model answer
\(8.4^2 + 5.1^2 = 70.56 + 26.01 = 96.57\) and \(\sqrt{96.57} = 9.827\ldots = 9.83\).
Mark scheme
- \(70.56 + 26.01 = 96.57\) — M1
- \(9.827\ldots\) — A1
- \(9.83\) — A1
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6 Work out [3 marks]
A car travels 148 miles in 2 hours 45 minutes. Work out the average speed of the car in miles per hour. Give your answer correct to 1 decimal place. (3 marks)
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Model answer
2 hours 45 minutes is 2.75 hours. Average speed \(= \dfrac{148}{2.75} = 53.8\) mph.
Mark scheme
- \(2.75\) hours — M1
- \(\dfrac{148}{2.75}\) — M1
- \(53.8\) — A1
Quick check
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1
Which mode must a calculator be in to find angles in a GCSE trigonometry question?
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B: Degrees
GCSE angles are measured in degrees.
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2
Which key do you use to enter \(3.2 \times 10^5\)?
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A: EXP
EXP enters the times ten to a power part.
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3
What does the Ans key do?
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D: Recalls the last answer
Ans holds the previous result.
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4
What should you type to work out \(\dfrac{5.6 + 3.2}{4.1 - 1.7}\)?
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C: \((5.6 + 3.2) \div (4.1 - 1.7)\)
Brackets are needed round both the top and the bottom.
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5
What is \(1500 \times 1.03^4\) to the nearest penny?
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B: \(\pounds 1688.26\)
\(1.03^4 = 1.1255\ldots\), and \(1500 \times 1.1255\ldots = 1688.26\ldots\).
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6
\(\tan\theta = \dfrac{7}{12}\). What is \(\theta\) to 1 decimal place?
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A: \(30.3^\circ\)
\(\theta = \tan^{-1}\left(\dfrac{7}{12}\right) = 30.256\ldots\).
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7
What is \(\sqrt{8.4^2 + 5.1^2}\) to 3 significant figures?
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D: 9.83
\(8.4^2 + 5.1^2 = 96.57\) and \(\sqrt{96.57} = 9.827\ldots\).
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8
Why should you avoid rounding in the middle of a calculation?
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C: It makes the final answer less accurate
Rounding early builds up errors.
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9
A train travels 215 km in 2 hours 36 minutes. What is its average speed to 1 decimal place?
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B: 82.7 km/h
2 hours 36 minutes is 2.6 hours, and \(215 \div 2.6 = 82.69\ldots\).