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.
