The children more or less run the session themselves; you hardly notice it’s happening. Each class has Quick Maths monitors, who give out the pocket-sized books, and coloured cards - different colours according to what level they are on - with up to 40 sums on each. They work in silence for five minutes, timed by the teacher, who tells them “you’ve had two minutes”, “time’s almost up”, and they do as much as they can.

Then, more monitors hand round cards with the answers on, and the children mark their own work. They enter their correct score out of 40 (for the juniors) on their own graph, which shows how their score has fluctuated in the preceding weeks. They have to get 40 out of 40 for a whole week before they can move on to the next colour and more difficult sums.

The juniors work up from red, yellow, green to blue, with only a few ever getting on to grey - which they see as a great event. The sums get more difficult, multiplication and division as well as addition and subtraction, and the more advanced include fractions and decimals. The infants have between eight and 20 sums to do, beginning with pictorial ones.

The idea is that you go at your own pace: the competition is against yourself. One of the good things is that nobody else has to know what score you got. I don’t find they compare themselves with one another.

When we first started doing it, nearly two terms ago, I thought they would cheat, and look back in their books at their old answers. But only a few did - and they’ve stopped now. They’ve realised there’s no point in getting on to a card that is too difficult.

Chris Hotham, headteacher here since last September, brought the idea of Quick Maths with him from Wiltshire, where it has been quite widely used. He sent me on a maths course run by Islington. The research had just come out showing that Swiss children who do more mental arithmetic are up to two years ahead of ours in maths, and so there was a lot of interest in Quick Maths. I gave photocopies of our cards to a number of other teachers on the course, and at least four or five have set the scheme up in their own schools.

It is quite a big commitment in terms of time and money. It took us more than a term just to make all the cards - we’ve got about 7,000 - with help from a few parents; it was extremely laborious because all the cards had to have sticky-backed plastic put on by hand. Each class has two boxes, containing number cards and answers, and we’re in the process of introducing new colour levels; as the scheme progresses, younger and younger children are needing harder and harder cards.

Initially, I was worried the children would get bored - but they don’t. They love it, and they feel cheated if they don’t get it. Lateness is less of problem, too, because they don’t want to miss it. I think the children like the chance to sit in silence and focus on a piece of work, knowing what’s expected of them, and I can tell that the children are feeling more confident.

The teachers love it, too. Quick Maths is a guaranteed, peaceful start to the day. The children are really using their brains, and everybody knows where they stand. A lot of teachers find the maths curriculum quite overloaded, and worry that number is not always being covered thoroughly enough: this is a way of helping.

Some try counting on their fingers, but they find there is a quicker way; the only way you can get 40 out of 40 is if you know some of the answers from memory. We’re trying to change our methods, so that children are less reliant on mechanical ways of working things out, by always putting numbers in tens and units columns - and have more number facts in their heads. We also learn tables, and I would love to put some of the Swiss methods - oral mental arithmetic with the class - into practice, too.

Teachers from other schools come in to see what we’re doing, and all of them say they hope they can do the same. Patrick Eve, from the Institute of Education in London, and Hazel House, an Islington maths adviser, have set up a research project on it.

Our school and several others are involved; we’ll be interviewing six children from each class, of above average, average and below average ability, to see how they solve problems, and monitoring their progress over the next year.

Susie Weeds is maths co-ordinator and Year 5 and 6 teacher at Tufnell Park Primary, north London

Menu: for Quick Maths sessions, Tufnell Park Primary uses: one box of question cards for each class and one box of answer cards; a little book for each child to record answers and a graph to chart results