They are often able to put across difficult concepts such as multiplication and division in a way their peers can more easily understand, according to Mike Askew, of King's College, London.
Dr Askew, deputy director of the five-year Leverhulme Numeracy Research Programme, has been looking at why some primary children struggle with maths.
"Children make a lot of use of their peers, and in some circumstances do learn from each other. We have been surprised by how infrequently teachers cash in on that," he said.
"The potential is there to make more use of children supporting each other, for example by asking them to use each other's methods.
"Another technique is to get children to work on a calculation in pairs and then toss a coin to see who will explain their method to the class. They sort out first who is heads and who is tails, but won't know which one is going to explain until the last minute, so neither can duck out of doing the work."
Dr Askew said children can find multiplication and division problematic. Division, for example, is introduced as both repeated subtraction and a way of sharing a number of objects between people.
He added: "When you have a calculation of 42 divided by six, whether you describe it as sharing 42 apples between six children or repeatedly subtracting six from 42 makes quite a big difference to children's appreciation of whether or not they can do the calculation.
"In some lessons teachers were not aware of the need to make that distinction. When you look at the National Numeracy Strategy, there is no detail spelling out to teachers why it is important."
Teachers need more than mathematical knowledge, he said, they need to be aware of these underlying steps.
As part of the study, he questioned 12 teachers about their experiences of maths teaching over two-and-a-half years.
The National Numeracy Strategy team and the Office for Standards in Education have previously raised concerns that the improvement in maths in infant classes seems to falter in Years 3 and 4.
OFSTED said earlier this year that although schools had made significant progress in teaching maths, errors or misconceptions in pupils' recording of calculations are not always tackled.
A Department for Education and Skills spokesman said: "This is very helpful research and matches our thinking too. We have been piloting materials over the past year to help teachers teach different aspects of calculation more rigorously and make use of children in explaining ideas and strategies to their classmates. This research may well help us to develop this work."