GCSE Maths: show your working and avoid silly mistakes

In GCSE Maths, a lot of marks are lost on questions students can do. The answer is right in their head, but the working is missing, a sign is wrong or the question was misread. These tips help you keep those marks.

1. Always show your working

Most questions give method marks, not just a mark for the final answer. If your final answer is wrong but your method is right, you can still get most of the marks. With no working, a wrong answer scores zero.

Good working is:

• written in order, one step per line,
• clear enough for someone else to follow,
• kept on the page (do not rub it out; just cross it out neatly if you change your mind).

2. Read the question twice

Underline the key parts: give your answer to 2 decimal places, in cm², as a fraction in its simplest form. Many marks are lost by answering a slightly different question.

3. Watch out for these common slips

• Negative numbers: −3 × −4 = +12, but −3 − 4 = −7.
• Order of operations: brackets, powers, then × and ÷, then + and −.
• Units: convert before you calculate (e.g. cm to m).
• Rounding too early: keep full values until the final step.
• Copying errors: check you copied the numbers from the question correctly.

4. Check your answer

Ask: does this make sense? A person's height is not 17 m. A probability cannot be more than 1. If you have time, use a different method, or work backwards to check.

5. Beat the non-calculator paper

Practise these without a calculator until they are quick:

• times tables and short division,
• long multiplication (column or grid method),
• fractions: add, subtract, multiply and divide,
• percentages of amounts (10%, 5%, 1% and build up),
• square numbers up to 15² and cube numbers up to 5³.

6. Use your formula sheet, but know it too

In recent exam years, students have been given a formula sheet in GCSE Maths. Check with your teacher what applies for your exam year. Even with a sheet, knowing the common formulas saves time.

In short

Show every step, read the question twice, check your answer and practise non-calculator skills. These simple habits can add a whole grade to your result.