# Science calculations

Maths questions often start with the command words 'calculate' or 'determine'. They will then have a blank space for you to show your working. It is important that you show your working; don't just write the answer down. You might earn marks for your working even if you get the answer incorrect.

In some maths questions you will be required to give the units. This may earn you an additional mark. Don’t forget to check whether you need to do this.

Maths questions might include graphs and tables as well as calculations. Don’t forget to take a ruler and calculator.

If drawing graphs, make sure you:

• put the independent variable on the x-axis and the dependent variable on the y-axis
• construct regular scales for the axes
• label the axes appropriate
• plot each point accurately
• decide whether the origin should be used as a data point
• draw a straight or curved line of best fit

If you are asked to calculate an answer and it has lots of decimal places, don't forget to use the same number of significant figures as the data in the question. For example, if two significant figures are used in the question, then usually your answer would also be to two significant figures. Don’t forget to check your rounding.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

## Sample question 1 - Foundation

Question

What is the total magnification of a light microscope with an eyepiece lens of ×10 and an objective lens of ×40? [1 mark]

10 × 40 = ×400 [1]

Total magnification of microscope = magnification of eyepiece lens × magnification of objective lens

## Sample question 2 - Foundation

Question

How many orders of magnitude exist between an ant which is 3 mm long and a human hair which has a diameter of 100 μm? [3 marks]

Ant = 3 mm which is 0.003 m or 10−3 m [1]

Human hair = 100 μm which is 0.0001 or 10−4 m [1]

So there is one order of difference. [1]

## Sample question 3 - Higher

Question

If a drawing of a cell in a textbook is 1 cm and the scale shows it to be 0.1 mm in real life, what is its magnification? [2 marks]

1 cm = 10 mm [1]

So, 10 mm ÷ 0.1 mm = ×100 [1]