GCSE Maths Higher · AQA · Algebra
The five GCSE Maths Higher mistakes examiners flag every series
Every AQA GCSE Maths Higher mark scheme highlights the same handful of misconceptions in its examiner's report — and the same handful resurface in the next series, then the one after that. The patterns are durable. They aren't carelessness; they're predictable shortcuts the brain takes when maths is read like English.
Below is the full set as of the current AQA specification. Each page names the misconception, explains why it happens, shows a worked example, and gives you a thirty-second technique to fix it. If you want to know which ones you personally fall for, the free 10-minute diagnostic will tell you.
Which ones are costing you marks?
The 10-minute diagnostic tests for all five with AQA-style items. You get a grade-band prediction and a list of which patterns to fix first. Free, no signup, anonymous.
Mixing up m and c — the most common GCSE Higher Algebra mistake, costing two to three marks per paper.
Computing Δy instead of Δy ÷ Δx — confusing total vertical change with the rate of change per unit.
Dropping the minus sign on descending lines — the magnitude is right but the direction is lost.
Not recognising that y = 4 + 2x and y = 2x + 4 are the same equation — examiners reorder deliberately.
Getting the maths right but the explanation wrong — “the gradient is 4” with no units or per-unit phrase.