Traditional whole-class teaching is switching young children off maths, according to new research.
Such teaching is a key feature of the numeracy strategy introduced by the Government to raise maths standards in primary schools.
A major study of early mathematics, however, has found that whole-class teaching can shatter the confidence of low-attaining five to seven-year-olds and act as a brake on their achievement.
Improvements in the maths test scores of seven-year-olds are a result of teachers teaching to the test rather than any increase in pupils' understanding, a report to be published next month will say.
Pupils at the top of the class are also losing out as teachers struggle to engage children of differing abilities.
The findings of the research, commissioned by the Evidence Informed Policy and Practice Co-ordinating (EPPI) Centre, will reignite the debate about how much of the improvement in primary literacy and numeracy test scores is the result of real changes in achievement.
A Durham study, published in 2002, found maths standards had improved since 1997 but that reading had not, despite big increases in test scores. The EPPI centre report, a systematic review of existing research on the impact of the numeracy hour and the Government's wider numeracy strategy on key stage 1 pupils, could also help explain why results for 11-year-olds have stalled.
Low-attaining boys are particularly likely to be disaffected if their lack of mathematical skill is exposed at an early age in whole-class question and answer sessions, the study found.
The fast pace set by the national numeracy strategy also contributes to disaffection, as struggling pupils often move on to a new topic before they have properly grasped the previous one.
Teachers' failure to ensure that whole-class teaching actively involves pupils and encourages them to think strategically means lessons do not challenge and extend the thinking of pupils, researchers found.
This is exacerbated by a lack of subject knowledge among teachers, hindering implementation of the numeracy strategy.
The study acknowledges that teachers and heads believe daily maths lessons have improved the confidence and competence of pupils but says their opinion is likely to be influenced by improvements in test scores and suggests benefits have been restricted to pupils of average ability.
Dr Chris Kyriacou, of York university, one of the authors of the study, said: "Teachers are spending more time teaching to the tests without increasing pupils' understanding."
Dr Tony Gardiner, Birmingham university reader in maths and maths education, said: "Most of the Government's claimed improvement in numeracy has come from teaching to the tests and from improvements by pupils in the middle.
"The two ends of the ability range have been very badly served," he said.
Kevan Collins, director of the national primary strategy, admitted that there is a "long legacy" of failing to help low achievers in maths. But he said catch-up sessions are now being introduced to help ensure low-achieving pupils have a secure grasp of the key concepts. Teaching to the tests should stop with the Government's announcement earlier this term that a greater emphasis would be placed on teacher assessment of seven-year-olds, he added.
The report calls for in-service training to improve teachers' knowledge of maths and to help them make whole-class teaching more "interactive".