How to Show Your Working

Working = Marks

In GCSE Mathematics, your working is often worth more than your answer. Examiners award method marks even when your final answer is wrong.

Why Working Matters

Consider a 4-mark question where:

• M1 = Using the correct formula
• M1 = Correct substitution
• M1 = Correct algebraic manipulation
• A1 = Correct final answer

If you make a calculator error but showed all your working, you could score 3/4 marks.

If you just write the wrong answer with no working: 0/4 marks.

The Golden Rules

Rule 1: One step per line

❌ Bad layout: $2x + 5 = 17$ so $2x = 12$ so $x = 6$

✅ Good layout: $2x + 5 = 17$ $2x = 17 - 5$ $2x = 12$ $x = 6$

Rule 2: Show substitution explicitly

When using a formula:

1. Write the formula
2. Show what you're substituting
3. Calculate

For area of a circle with radius 5: $A = \pi r^2$ $A = \pi \times 5^2$ $A = 25\pi$ $A = 78.5$ cm² (3 s.f.)

Rule 3: Keep your working even when you change your mind

If you realise you made a mistake:

• Cross out neatly with a single line
• Write the correct version nearby
• Don't scribble or use correction fluid

Examiners can give marks for crossed-out work if your new answer is wrong!

What Counts as Working?

Essential to show:

• Formulae you're using
• Substituted values
• Intermediate calculations
• Units (at least in your final answer)

Helpful to show:

• What each line represents (brief labels)
• Rough diagrams or sketches
• Checking calculations

Not necessary:

• Calculator button presses
• Obvious arithmetic (like 5 + 3 = 8)
• Multiple rewrites of the same thing

Subject-Specific Guidance

Algebra:

• Show each manipulation step
• Write "= 0" when solving equations
• State your answer clearly at the end

Geometry:

• Always state the rule or theorem you're using
• Label diagrams with given information
• Show angle calculations step by step

Statistics:

• Show your lists, tallies, or tables
• Write out calculations for mean, etc.
• Draw diagrams accurately with a ruler

Graphs:

• Show how you found key points
• Include coordinates you calculated
• Label axes and intercepts

Error-Carried-Forward Marks

If you make an error early in a question:

• Continue with your wrong answer
• You can still earn marks for correct method applied to your incorrect value
• This is called "error-carried-forward" or ECF

Example: You calculated the first side of a triangle as 8 cm (it should be 6 cm).

If you then correctly use Pythagoras with your 8 cm: $c^2 = 8^2 + 10^2 = 164$ $c = 12.8$ cm (1 d.p.)

You'd get method marks even though your answer (12.8) differs from the correct answer (11.7).

The "Show You Know" Approach

Even if you can't finish a question:

• Write down relevant formulae
• Show what you would substitute
• Describe your approach in words if necessary

Something is always better than nothing!