Almost half of England's schools are not teaching mathematics well enough, putting too much emphasis on "teaching to the test", inspectors have said.
Ofsted said pupils were taught to pass exams and results had improved, but understanding of the subject had not.
Teaching and learning, the curriculum and management were all stronger in primary schools than secondary schools.
The government said it was investing £140m in measures "to transform the standard" of maths teaching in England.
Ofsted said its report, Mathematics: Understanding the score, was based principally on evidence from inspections undertaken between April 2005 and December 2007 in 192 maintained schools in England, 84 primary and 108 secondary.
Many secondaries had big problems finding good teachers. Pupils' progress was inadequate in one in 10 lessons, Ofsted said.
The effectiveness of work in maths was judged to be outstanding in 11%, good in 44% and satisfactory in 40% - by an inspectorate which regards "satisfactory" as not being good enough.
Of the nine schools where the quality was deemed to be inadequate, six were secondary schools.
The report said there had been a steady improvement in test and examination results
Key Stage 3 results - from the tests taken by pupils aged 13 and 14 - were improving and a greater percentage of pupils reached the vital threshold of grade C at GCSE level.
"But this does not tell the whole story," Ofsted said.
"Based on the gains made at Key Stage 3, more pupils than at present should be reaching the higher GCSE grades.
"Evidence suggests that strategies to improve test and examination performance, including 'booster' lessons, revision classes and extensive intervention, coupled with a heavy emphasis on 'teaching to the test', succeed in preparing pupils to gain the qualifications but are not equipping them well enough mathematically for their futures.
"It is of vital importance to shift from a narrow emphasis on disparate skills towards a focus on pupils' mathematical understanding."
Pupils should be taught to make sense of mathematics - so they could use it confidently in their everyday lives and were prepared for further study and the workplace.
Chief inspector Christine Gilbert said: "The way mathematics is taught can make a huge difference to the level of enthusiasm and interest for the subject.
"As well as developing fluent numeracy skills to deal with everyday mathematics, children and young people need to be able to think mathematically, model, analyse and reason."
She added: "We all benefit from the advanced mathematics that underpins our technological world.
"We need children to be equipped to use mathematics with confidence in and beyond the classroom to play their part in a rapidly changing society."
Among a series of recommendations, Ofsted said the Department for Children, Schools and Families should reintroduce separate reporting of pupils' attainment in "using and applying mathematics".
The National Centre for Excellence in the Teaching of Mathematics - set up after a previous critical inquiry into maths teaching in England - should help teachers assess their own knowledge, get access to training and share good practice.
To an extent Ofsted's report has been overtaken by a later review the government commissioned, by Sir Peter Williams, which was published in June.
Accepting his findings, ministers said 13,000 maths specialists would spearhead better primary school teaching. It will take 10 years to train them.
England's Schools Minister Jim Knight said: "While Ofsted recognises there are positive trends, with results in maths up at all ages, we know that more needs to be done to improve maths for the long term.
"That’s why we are introducing a whole range of measures, backed by £140m, which will transform the standard of maths teaching in this country.
"Good teachers know that the best way to ensure pupils make good progress – and to pass exams and tests - is to give them a broad, in depth understanding of the subject. There is no reason why testing should result in a narrow focus or uninspiring lessons.
"This year’s new secondary curriculum will help bring mathematics to life. It will promote better mathematical thinking and problem solving as well as developing pupil's confidence in maths and their ability to apply maths in real life, relevant contexts."
6 months ago