Pupils who shine in maths GCSE exams often fail to understand the subject and are poorly equipped to do A-levels, inspectors report today.
A survey of secondary school maths teaching by Ofsted, the education standards watchdog, accused teachers of "teaching to the test" but failing to pass on a basic understanding of the subject.
The situation was exacerbated by one in three classes being taken by untrained teachers - because of a shortage of maths recruits. The report states: "Inspectors found evidence of 'teaching to the test' with students being taught how to obtain answers but not what their answers meant."
Miriam Rosen, director of education at Ofsted, said: "At present too many students do not expect to understand mathematics. Students try to pass exams by memorising lots of unconnected facts rather than a few guiding principles.
"The current approach to teaching mathematics is not giving students the understanding they require and this must change."
The report is highly critical of teaching standards, saying teachers often talk for too long and fail to encourage practical or group work or discussion.
Many did not possess enough subject expertise themselves to deliver the lesson effectively.
"In many of the lessons seen, the teaching had some strengths but lacked sufficient flair, imagination and challenge to get the best from students," the report says. "In a few of the lessons seen, teachers gave students incorrect, incomplete, inappropriate or misleading information."
It adds: "In areas where recruitment and retention of mathematics teachers were a problem, schools sometimes had to rely on unsuitable staff.
"Some students attending colleges in these areas complained to inspectors that they had been taught by several different temporary teachers during key stage four (covering lessons for 14- to 16-year-olds) in the run-up to GCSEs."
The report concludes that - while more than half of the lessons observed were at least satisfactory - "there was also much that did not develop students' capabilities beyond the basic competencies required to pass examinations".
"Some centres focused single-mindedly on the examination requirements, often supported by intensive 'drill and practice' revision activities, and their students achieved good examination results," it says.
"Some practice is necessary but the danger of using such an approach exclusively is that it gives a temporary boost that is not sustained at the next examination level."
The findings were dismissed by ministers last night. The new schools minister, Jim Knight, said: "We do not accept that tests can be passed without properly mastering and understanding the subject."
Nick Gibb, Conservative schools spokesman, said the report confirmed "the crisis in maths teaching".Reuse content