Your child's maths marks dropped suddenly — what to check first

4 September 2026 · by Larry

A paper comes home and the mark is a lot lower than the last one. Nothing obvious has changed at home. The first thought is usually that something has gone wrong — with the child, with the teaching, or with your own attention to it.

Most of the time it is something much smaller than that, and it is findable in about twenty minutes if you look in the right order. The order matters, because the natural response is to act first — extra practice, a talk, a tutor — and every one of those is the wrong move if you have not worked out what actually happened.

Before anything: look at the paper, not the number

The mark is a summary, and summaries hide the useful information. What you want is the shape of the losses, and you get it by going through the paper question by question with a pencil and putting each lost mark into one of four piles.

• Did not know the topic. Blank, or an attempt that has nothing to do with the method.
• Knew it, made a slip. Right method, wrong arithmetic, or a copied number that changed on the way down the page.
• Misread the question. A correct answer to a question that was not asked.
• Ran out of time. The last section thinner than the rest, or blank.

Those four piles need four completely different responses, and they are frequently mistaken for each other. A child who lost twelve marks to slips does not need more topics taught; a child who ran out of time does not need more accuracy drills. Sorting first is what stops you spending a term on the wrong thing.

If most of the losses are in the second pile, careless mistakes and what they usually are goes through what is actually happening in each type. If marks went missing on questions where the answer was right, that is a different problem again and it is covered in right answer, but the marks still went.

The most common explanation, and the least alarming

Two papers are rarely the same difficulty, and a term's topics are not evenly hard.

A paper that is mostly fractions and one that is mostly measurement are two different tests of the same child. So are a topical test on material covered last week and an end-of-term paper covering four months. A mark that falls between them may be telling you nothing about a decline at all — it may be telling you that one topic did not land while everything around it did.

The check is simple: are the lost marks concentrated in one topic, or spread across the paper?

Concentrated is good news, oddly. It means one identifiable thing is missing, and one thing can be fixed. Spread evenly across topics is the pattern worth paying more attention to, because it usually points at something that is not about content — timing, reading, confidence, or attention.

Check the calendar before you check the child

This sounds too simple and it is the thing most often skipped.

Was the paper sat during a week with something else in it? A bad cold. A late night. A test in another subject the same morning. A change of class or teacher. Something at home. Children are not consistent machines, and a single result taken on a poor day is a data point about that day.

Watch out for something specific here: an improving child can produce a lower mark on a harder paper, and a child who has stopped putting effort in can produce a stable mark for a while. The number alone does not distinguish those. The paper does.

The practical rule I use is that one result is an event and three results are a pattern. If this is the first low mark after a run of steady ones, note it, look at the paper, and wait. If it is the third, that is a different conversation.

Then check whether the work got harder in a step

Maths does not get harder evenly. There are a few points in primary school where the demand changes shape rather than degree, and a child who was fine before can genuinely struggle straight afterwards without anything having gone wrong.

The move from P2 to P3 is the clearest of them, and it catches a lot of families by surprise — what actually changes between P2 and P3 sets out why. Fractions are another, and they tend to break quietly and late, which is covered in fractions, when they stop making sense.

The other shift is one nobody announces: at some point the questions stop being sums and start being stories. A child whose arithmetic is completely sound can lose a lot of marks the term that happens, and it reads exactly like a maths problem when it is not one. Word problems when the sums are fine but the story is not is about that.

The three quiet causes people miss

Time. If the last page is thin or blank while everything before it is correct, the child does not have a maths problem, they have a pace problem. This is one of the few things that genuinely does respond to practice — but practice of a specific kind, and it can be made worse by the obvious approach. Timing your child, and when it helps covers where the line is.

Working on paper. Children who have been doing a lot of practice on a screen, or in their heads, sometimes stop writing anything down. It works right up until the questions get long enough that the head cannot hold them all, and then several marks go at once. When they can do it on screen but not on paper is about that gap.

Confidence. A child who has decided a topic is beyond them will stop attempting the questions, and blank answers look identical to not knowing. If the blanks are on questions you know they can do, this is where to look — freezing on a question they know and when they say they are bad at maths both cover it.

What to ask the teacher

If you get one message or one short conversation, general questions get general answers. Ask something specific instead:

• Was this paper harder than the last one, or a different set of topics?
• How did the class do overall — did the average move too?
• Did you see anything in the working that concerned you, as opposed to the mark?
• Is there one topic you would work on if you were me?

The second question is worth more than it looks. If the whole class dropped, you are looking at a paper, not a child, and you can stop worrying about the number and go back to the working.

What not to do this week

Do not buy a stack of assessment books on the strength of one paper. Until you know which of the four piles the marks came from, more practice is as likely to reinforce the problem as fix it. Choosing assessment books and how many covers what to do when you do reach that point.

Do not add a tutor on the same evidence. Not because tutors are wrong, but because a tutor given a mark and no diagnosis will start at the beginning, which is expensive and often not where the gap is. What to try before getting a tutor goes through the sequence.

Do not make the paper into an event. The child already knows the mark was bad. A long conversation about it teaches them that a low mark produces a difficult evening, and the reliable way to avoid a difficult evening is to stop showing you the papers.

The short version

Sort the lost marks into four piles — not known, slip, misread, ran out of time — because each needs a different response. Check whether the losses are concentrated in one topic or spread across the paper; concentrated is easier to fix. Ask what else was happening that week, and whether the paper was simply harder. Treat one result as an event and three as a pattern. Ask the teacher whether the class average moved. And hold off on books and tutors until you know what you are buying them for.

Most of the time this ends with something small and specific: one topic that did not land, or a page nobody had time to reach. Both of those are fixable, and both are much easier to fix in September than in a fortnight before an exam.

And if the thing that prompted the worry was another child's mark rather than a fall in your own child's, comparing your child to their classmates covers what that comparison can and cannot tell you.