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Using a Calculator

FoundationHigherAQAEdexcelOCR

Get to grips with using a calculator using these Foundation and Higher GCSE Maths practice questions. The worksheet focuses on using a calculator efficiently, and the accompanying mark scheme breaks down each solution clearly. Suitable for AQA, Edexcel and OCR. Download the questions and answers for free. Use brackets to control the order of operations, especially with fractions.

Free downloads

These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.

Foundation

WorksheetFoundation · PDFMark SchemeFoundation · PDF

Higher

WorksheetHigher · PDFMark SchemeHigher · PDF

Topic overview

Using a calculator well is a genuine skill, and marks are lost by students who type expressions in without thinking about the order of operations.

The calculator applies BIDMAS to exactly what you type, which may not be what you intended. Typing a fraction as \(6 + 14 \div 5\) gives \(8.8\), because only the \(14\) is divided. The bracket keys or the fraction key are needed to make the intention clear.

The other essential habits are keeping full accuracy until the end and knowing the key functions: the fraction key, powers, roots, brackets, the memory keys and the standard form key. Rounding partway through introduces errors that compound.

Revision notes

Brackets and fractions

A fraction line acts as a bracket around the whole numerator and denominator, so it must be typed with brackets or the fraction key.

For \(\frac{6 + 14}{5}\), type \((6 + 14) \div 5\) to get \(4\). Without brackets the calculator gives \(8.8\).

Keeping full accuracy

Work with the calculator's full value throughout and round only the final answer. Use the answer key to carry a value forward rather than retyping a rounded version.

Rounding partway is a common source of answers that are close but not close enough for the accuracy mark.

Useful functions

Know where the fraction, power, root, bracket and standard form keys are, and how to enter negative numbers using the sign key rather than the subtract key.

Check your calculator is in degrees mode before any trigonometry, since radians will give completely wrong answers.

Key points

  • The calculator applies BIDMAS to exactly what you type.
  • Use brackets around a numerator and denominator.
  • Keep full accuracy until the final answer.
  • Use the answer key to carry values forward.
  • Use the sign key, not subtract, for negative numbers.
  • Check the calculator is in degrees mode for trigonometry.

Worked examples

Example 1

Use a calculator to work out \(\dfrac{18 + 27}{9}\).

Working

\[(18 + 27) \div 9\]type brackets around the numerator
\[45 \div 9 = 5\]the calculator evaluates the bracket first

Example 2

Work out \(\sqrt{6.4^2 + 3.9^2}\), giving your answer to 2 decimal places.

Working

\[6.4^2 + 3.9^2 = 56.17\]evaluate inside the root first, keeping full accuracy
\[\sqrt{56.17} = 7.4946\ldots\]take the square root without rounding first
\[= 7.49\]round only at the end

Example 3

Explain why typing \(6 + 14 \div 5\) does not give \(\frac{6+14}{5}\).

Working

\[\text{Division is done before addition}\]the calculator applies BIDMAS
\[6 + 2.8 = 8.8\]only the 14 is divided by 5
\[\text{Brackets are needed}\]type (6 + 14) ÷ 5 to get 4

Common mistakes

  • Typing a fraction without brackets.

    The calculator divides only the last term, so use brackets or the fraction key.

  • Rounding partway through.

    Errors compound. Keep full accuracy and round once at the end.

  • Using the subtract key for a negative number.

    Most calculators need the separate sign key for negatives.

  • Leaving the calculator in radians.

    Trigonometry answers will be completely wrong. Check for the D or DEG indicator.

Exam tips

  • Type brackets generously — they cost nothing and prevent order errors.
  • Write down intermediate values, but carry the unrounded value forward.
  • Check the mode indicator before any trigonometry.
  • Sense-check the answer against a rough mental estimate.

Key terms

BIDMAS
The order of operations a calculator follows.
Full accuracy
Keeping all decimal places until the final rounding.
Degrees mode
The setting needed for GCSE trigonometry.
Answer key
The key that recalls the previous result.

Related topics

Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.