School Has Started: How to Add Mental Arithmetic Without Overloading Your Child

Every September parents ask the same question: "School is already a full load — if we add mental arithmetic on top, will my child cope?" It is a fair question and it deserves a straight answer. What follows contains no promises of miracles: how much time this really takes, when you should not start at all, and what the first month actually looks like.

"We have no time" — the honest answer

Most people picture mental arithmetic as an hour-long lesson three times a week. In reality, calculation skill grows from short, regular repetition, not from long sessions. Ten to fifteen minutes a day, five days a week, is a realistic schedule. One weekly hour gives almost nothing, because the skill cools off across the six days in between.

So the question is not "can we find an hour" but "can we find fifteen minutes". If the answer is still no, the problem is the schedule rather than mental arithmetic, and it is more useful to first sort out your child's daily routine.

Why it eventually reduces the school load

The counter-intuitive part is that after a few months this skill cuts the school load. The reason is simple: much of the time spent on maths homework goes not into understanding the problem but into slow counting. A child who recounts every addition on their fingers spends three times as long per exercise and makes more mistakes along the way.

Once mental calculation is automatic, attention is freed for the meaning of the problem. How this works is explained in detail in the article on what mental arithmetic actually is. In practice, after two or three months maths homework tends to take fifteen to twenty minutes less.

When not to start

"Now" is not always the right moment. In three situations it is wiser to wait:

• The first three or four weeks of the school year. Your child is adjusting to a new timetable, new expectations and a new group. This matters most for first-graders, where what to watch in month one is a topic of its own.
• The schedule is already full. With a club, a sport and a tutor in place, there is nothing to add — something should come out first.
• Your child is in a rough patch. A move, a change at home, disrupted sleep — new practice at such a time only produces resistance.

Waiting two or three weeks costs you nothing. A bad start that makes practice feel like one more obligation takes months to undo.

Where fifteen minutes fit into a school day

Do not leave it for "whenever there is a gap" — the gap never appears. Three slots work:

• In the morning, before school. The mind is fresh and attention is high. The one condition is that it must not be rushed.
• After school and a proper break, before homework. This is the most reliable option: a short drill warms the brain up, and homework starts more easily. It fits naturally into a calm homework routine.
• After dinner, but at least an hour before bedtime.

Avoid practising right before sleep: your child is tired, errors multiply, and the day ends on a sour note.

Start with one method, not everything

The most common mistake is introducing everything at once. The right order is stepwise: first small friends, the pairs that make five, and only once those are automatic move on to big friends, the pairs that make ten.

One method usually takes two to four weeks. "Automatic" means your child answers immediately instead of recalling the rule. Do not move to a new topic before that sign appears, or both techniques end up half learned.

What the first month really looks like

Reasonable expectations run like this. Week one is slow and awkward, with a lot of visible thinking. In week two the speed barely changes, but errors drop. Weeks three and four bring faster answers within the one method being practised.

Here is what will not happen in the first month: your child will not start calculating large sums in their head, school marks will not jump, and they will not sit down eagerly every single day. All of that is normal. Knowing it in advance stops you concluding in week three that "it isn't working".

Keeping it going when motivation drops

Motivation will drop, usually somewhere between week three and week five. The fix is not persuasion but shrinking the format: cut fifteen minutes to seven, but do not skip the day. A break costs far more than a weak session.

Alternating helps too: calculation one day, attention and memory games the next. If concentration difficulties persist, read the separate piece on how to improve your child's attention.

How to tell whether it is working

"Does he enjoy it?" is a poor measure. Track two concrete numbers instead: accuracy (the share of correct answers) and time per question. MentalMath records both automatically, but a notebook works as well — twenty exercises once a week, results written down.

Healthy progress means accuracy sitting somewhere between 70 and 85 per cent while the time per question slowly falls. If accuracy is consistently above 95 per cent the work is too easy; below 60 per cent it is too hard. If nothing changes across four weeks, the format or the time of day is wrong, and that is what to change.