Most parents helping with GCSE maths homework aren't stuck because they can't do maths — they're stuck because they haven't done this specific method, the way the exam board teaches it, in fifteen or twenty years. The good news: you don't need to remember the method to help. You need three questions.
"What is the question actually asking you to find?"
This sounds obvious, but it's the single most useful question in the whole toolkit, because a genuinely large share of wrong answers come from solving a slightly different problem than the one that was asked — finding the perimeter when the question asked for area, or stopping one step early because the answer "looked right" already. Asking a student to state, out loud, what they're solving for before they start often surfaces the mistake before a single number gets written down.
"What have you already tried?"
Not "what's the answer" — what have they tried. This does two things: it stops a homework session from turning into you doing the problem while they watch, and it usually reveals exactly where the stall is. A blank page means something different from a page with three false starts crossed out. The second case tells you they understand the type of problem but not the specific step — which is a much smaller, much more fixable gap.
"Can you show me on a simpler version of the same problem?"
If a student is stuck on, say, solving a quadratic with awkward numbers, ask them to try the same method on x² + 3x + 2 = 0 — something small enough to hold in their head. This isolates whether the method is the problem or the numbers are the problem, which are two completely different things to fix. Struggling with the simple version means the method itself needs more work. Getting the simple version instantly but failing the real one usually means arithmetic confidence, not understanding, is the actual gap.
What to avoid
The instinct to say "oh, I remember this — you do it like this" and demonstrate the method is the single easiest way to turn a useful homework session into an unhelpful one, because it replaces the student's own problem-solving with yours. If you genuinely don't remember the method at all, that's not a disadvantage here — it forces you into asking questions instead of giving answers, which is the more useful role anyway.