COMMAND WORD · BIOLOGY

Calculate

Work out the number from the data, show the working, and include the unit.

All command words

Method

Quantities, then the working, then the answer with its unit.

What the parts mean

Quantitiesthe numbers the question needs, with their units
Workingthe operation written out
Answerthe result and its unit

How to build your answer

1Write down only the measurements you will use.
2Show the calculation before the result.
3Add the unit the quantity needs.
4Check that the size makes sense.

Biology exemplar

Original question

An illustrative syringe collects 18 cm³ of gas in 6 minutes. Calculate the rate.

Annotated answer

Quantities18 cm³ and 6 min. WorkingRate = 18 ÷ 6. Answer3 cm³ min⁻¹.

The labels match the frame. Read them in order. This is one accurate route, not the only one.

Exam habit

Write the unit every time. A bare number can be a mass, a time or a rate.

Common pitfall

Dividing the wrong pair, or leaving the answer as 3 with no unit.

Exam-style question

3 marks

Based on a sample question

Mark points shown after marking

The drawing shows two wall thicknesses, A and B, measured on one artery.

Illustrative drawing with the readings printed: A is 0.40 mm and B is 0.70 mm.

Calculate the percentage increase in wall thickness from A to B. Show your working.

(3)

Answer%

Total for this question: 3 marks

Answer discussion

Change = 0.70 − 0.40 = 0.30 mm. Percentage increase = 0.30 ÷ 0.40 × 100 = 75%. A bare 75, with no route, hides the calculation.

Where this comes from

Unit 1 sample paper. Question 8 (a) asks for the percentage increase in artery-wall thickness along a labelled line on a photograph. Sample assessment, not a live paper.

Sample paper WBI11/01, question 8 (a) (3 marks), 2017 sample assessment. Question page · Mark scheme page

Sources

Pearson Biology specification · Sample assessment PDF