[discia] GCSE Maths › Number › Using a Calculator

Using a Calculator

discia.org 10 questions · 25 marks
Name Date
  1. Calculator 1 mark

    Use your calculator to work out the value of the reciprocal of \(0.0128\)

    Show answer
    78.125 (or \(\frac{625}{8}\), as a calculator may show it)
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  2. Calculator 2 marks

    Ben uses a calculator to work out \(46 + 17 \times 3\)

    He types \(46 + 17\), presses equals, then types \(\times 3\) and presses equals again.

    The display shows \(189\), which is not the right answer.

    (a)

    Calculate the correct value of \(46 + 17 \times 3\)

    (b)

    Explain what Ben did wrong.

    Show answer
    (a) \(97\)
    (b) He pressed equals after 46 + 17, so the calculator added first and then multiplied the whole of 63 by 3. The calculation should be typed in one go, without pressing equals in the middle.
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  3. Calculator 3 marks

    Leila wants to use a calculator to work out

    \(\frac{ 77.7 + 54.8 }{ 61 - 8 }\)

    (a)

    Write down the calculation Leila should type into the calculator.

    Use brackets in your answer.

    (b)

    Calculate the value of the calculation.

    Show answer
    (a) \((77.7 + 54.8) \div (61 - 8)\)
    (b) \(2.5\)
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  4. Calculator 4 marks

    A group of nine friends share the cost of a meal equally.

    The total cost is £48.41.

    (a)

    Use a calculator to work out how much each friend pays.

    Give your answer correct to the nearest penny.

    (b)

    Each friend pays the amount from part (a).

    Calculate how much the 9 friends pay altogether.

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    (a) \(\text{£}5.38\)
    (b) \(\text{£}48.42\)
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  5. Calculator 3 marks

    A rectangular plot is being priced by area.

    \(x = \frac{ 63 \times 45 }{ 4 }\)

    (a)

    Use a calculator to work out \(x\).

    Write down all the figures on your calculator display.

    (b)

    Write down your answer to part (a) correct to 2 significant figures.

    Show answer
    (a) \(708.75\)
    (b) \(710\)
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  6. Calculator 2 marks

    Use your calculator to work out

    \(\frac{ 6.72^2 }{ 4.375 } + \sqrt{ 5.7 }\)

    Give your answer as a decimal. Write down your full calculator display.

    Show answer
    \(12.70938728\)
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  7. Calculator 2 marks

    Calculate \(\dfrac{ 3.24 \times 10^{ 7 } }{ 3.6 \times 10^{ 7 } }\)

    Give your answer in standard form.

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    \(9 \times 10^{ -1 }\)
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  8. Calculator 2 marks

    Use a calculator to work out

    \(\frac{ 11.35 + 5.81 }{ 6 }\)

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    \(2.86\)
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  9. Calculator 3 marks
    (a)

    State the value a calculator gives for \((-41)^2\).

    (b)

    State the value a calculator gives for \(-41^2\).

    (c)

    Explain why the two answers are different.

    Show answer
    (a) \(1681\)
    (b) \(-1681\)
    (c) The brackets decide what is squared: in \((-41)^2\) the minus sign is inside, and in \(-41^2\) it is outside, so it is applied after the squaring.
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  10. Calculator 3 marks

    Here are two calculations.

    \(3^4\) and \(4^3\)

    They use the same two numbers, swapped round.

    (a)

    Use a calculator to work out both.

    (b)

    State which of the two is larger.

    Show answer
    (a) \(3^4 = 81\) and \(4^3 = 64\)
    (b) \(3^4\)
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discia.org Using a Calculator · sheet 1
Answers Using a Calculator · sheet 1
  1. 78.125 (or \(\frac{625}{8}\), as a calculator may show it)
  2. (a) \(97\)
    (b) He pressed equals after 46 + 17, so the calculator added first and then multiplied the whole of 63 by 3. The calculation should be typed in one go, without pressing equals in the middle.
  3. (a) \((77.7 + 54.8) \div (61 - 8)\)
    (b) \(2.5\)
  4. (a) \(\text{£}5.38\)
    (b) \(\text{£}48.42\)
  5. (a) \(708.75\)
    (b) \(710\)
  6. \(12.70938728\)
  7. \(9 \times 10^{ -1 }\)
  8. \(2.86\)
  9. (a) \(1681\)
    (b) \(-1681\)
    (c) The brackets decide what is squared: in \((-41)^2\) the minus sign is inside, and in \(-41^2\) it is outside, so it is applied after the squaring.
  10. (a) \(3^4 = 81\) and \(4^3 = 64\)
    (b) \(3^4\)
discia.org Using a Calculator · sheet 1