GCSE maths topics students struggle with the most

6th October 2025 by Anita Naik

GCSE maths is one of the most challenging subjects students face, with a range of topics, such as rearranging algebraic equations and navigating probability tree diagrams, regularly hitting the top ten list of frustrations. Difficulty with maths isn't simply about understanding concepts, but being able to apply them to problems, show your working out, and build logical arguments that examiners want to see. The good news is that once you learn the right strategies to tackle these problem areas, they do become much more manageable. Here's what you need to know.

GCSE maths topics students struggle with the most

• Algebra - equations and formulas

• Trigonometry

• Fractions, decimals and percentages

• Probability (and tree diagrams)

• Circle Theorems

Why is maths so hard?

GCSE maths is challenging for nearly all students due to its cumulative nature, abstract concepts, and the external pressure to achieve good marks. Given the implications of this subject, it's not surprising to hear that math anxiety among all students has emerged as the top obstacle to learning.

According to a new report, over 1,000 UK teachers identified maths anxiety as the top obstacle to learning, closely followed by a lack of support at home (52%) and insufficient additional support in the classroom (34%).

This anxiety often stems from students feeling overwhelmed by the sheer breadth of topics covered, as well as the more complex nature of some of them. Understanding which specific issues cause the most problems and why is the first step to building genuine confidence in the subject.

The most challenging GCSE maths topics

Algebra: equations and rearranging formulas

Why students struggle:

1. Abstract nature - moving from concrete arithmetic to symbolic thinking.

2. Symbolic mathematics refers to the use of symbols, equations, and images to represent and convey mathematical concepts and information.

3. Multiple steps are required in the questions.

4. Common errors: incorrect sign changes, distributing negatives.

5. Confusion between simplifying and solving.

6. Difficulty knowing when the equation is "fully solved"

How to master it:

• Understand the fundamentals: Think of equations as balanced scales.

• Practice inverse operations: BIDMAS backwards

• Check your answers thoroughly.

• Check for common mistakes: Losing negative signs when expanding brackets

Recommended practice: Start with one-step equations, gradually build complexity

Resource suggestions: Specific textbook pages, Corbett Maths videos.

Key GCSE maths exam tip: Show all working - method marks are available even if the final answer is wrong.

Trigonometry:

Why students struggle:

1. Three different ratios to remember and apply correctly. There are three trig ratios you need to know: sine, cosine, and tangent.

2. Knowing which ratio to use in different scenarios

3. Calculator errors (degree vs radian mode, using inverse functions)

4. Confusion between finding angles vs finding sides

5. Pythagoras vs trigonometry decision-making

6. Exact trigonometry values, graphs, and identities all add complexity to the subject.

How to master it:

• Use this memory technique: SOH CAH TOA song/mnemonic. These letters stand for: S sine O opposite H hypotenuse. C cosine A adjacent H hypotenuse. T tangent O opposite A adjacent.

• Label triangles systematically: Opposite, Adjacent, Hypotenuse relative to the angle.

• Decision-making flowchart: When to use which ratio.

• Common mistake to avoid: Forgetting to use the inverse when finding angles.

• Practice strategy: Do five problems finding sides, then five finding angles.

• Create a table of common angles (0°, 30°, 45°, 60°, 90°).

Key GCSE maths exam tip: Always round to 3 significant figures unless told otherwise.

Fractions, Decimals, and Percentages

Why students struggle:

1. Converting between the three forms under pressure

2. Percentage increase/decrease calculations

3. Reverse percentages (finding original amount)

4. Compound interest and depreciation complexity

How to master it:

• To quickly switch between fractions, decimals, and percentages, use this simple diagram. Fraction to decimal: Divide the numerator by the denominator. Decimal to percentage: Multiply by 100. Percentage to decimal: Divide by 100. Decimal to fraction: Use place value (e.g., 0.75 is 10075).

• Finding a percentage of a quantity. A simple rule of thumb: when calculating a percentage of a number, the word 'of' means multiply. Example: To find 30% of 80, calculate 0.30 × 80.

• To figure out a percentage increase or decrease, use this formula: Percentage Change=Original Amount Change×100.

• To quickly apply a percentage increase or decrease, use a multiplier. This is faster than calculating the percentage and then the addition or subtraction. For example: 15% Increase: The new total is 100% + 15% = 115%. The multiplier is 1.15.

• Mental maths shortcuts: 50% = half, 25% = quarter, 10% = divide by 10

Key Exam Tip: Show the multiplier method for percentage changes.

Probability

Why students struggle:

1. Confusion between independent and dependent events.

2. Tree diagram (a visual, branched diagram that maps out all possible outcomes and their probabilities for two or more sequential events) complexity with multiple branches.

3. Knowing when to multiply vs add probabilities in scenarios.

4. Conditional probability and set notation.

How to master it:

• Branch sum rule: The probabilities on any set of branches leading from a single point must always add up to 1.

• 'AND' rule (multiplication): To find the probability of a sequence of events (this and then that), multiply the probabilities along the relevant path.

• 'OR' Rule (Addition): To find the probability of one outcome or another outcome, add the probabilities of the separate, final routes.

• Drawing a tree diagram:

1. Always draw your branches clearly, showing all possible outcomes at each stage.

2. Write the probabilities directly onto the lines (the branches). Clearly label the end of each branch with the event it represents (e.g., 'Success', 'Fail', 'Red', 'Blue').

3. Begin by mastering simple two-stage tree diagrams before moving on to more complex three-stage scenarios.

4. Practice approach: Start with two-event trees, then progress to three events

Key Exam Tip: Write out the calculation clearly - don't try to do it in your head

Circle Theorems

Why students struggle:

1. Multiple theorems to memorise

2. Knowing which theorem applies to which diagram

3. Being able to provide the right geometric reasoning

4. Knowing how to combine multiple theorems

How to master it:

• Memorisation strategy: Create flashcards with a diagram on one side, a theorem on the other

• Key theorems list:

1. Angles in the same segment are equal.

2. The angle at the centre is twice the angle at the circumference.

3. Angle in a semicircle is 90°.

4. Opposite angles in a cyclic quadrilateral sum to 180°.

5. Tangent perpendicular to radius.

• Common mistake to avoid: Assuming angles are equal without geometric justification

Key Exam Tip: Draw on the diagram - mark equal angles, parallel lines, right angles with correct notation.

You should consider working with a tutor if you are:

Struggling with 3+ topics on this list consistently, and self-study, revision, and extra work are not producing improvements.

A tutor can also help if your mock results are significantly below the target grade you want and you feel anxious or overwhelmed by maths generally (not just the points above).

The right tutor can build maths confidence, exam technique and help you fill knowledge gaps.