Signs your child may be stuck
Homework takes far longer than it should, or doesn't get done. Test marks drop even though they say they studied. They can follow an example in class but can't do the next question on their own. They start saying they're "just bad at maths".
What to say
Ask which topic feels worst instead of asking how they did. Keep it calm and specific. Students open up when you're talking about fixing one topic and not about whether they're any good.
Practical steps at home
Ask them to walk you through one worked question, step by step. If they can't, you've found the gap. Little and often beats one long session at the weekend. Use past exam questions on whichever topic they find hardest.
When to get extra help
If the same topics keep tripping them up for weeks, or their confidence is sinking, extra help is worth it. Look for support between lessons and not only a weekly hour, and a way for you to see how they're doing. A free first grind lets you judge the fit before you pay.