Carol Vorderman says pupils should study maths to 18
School pupils in England should study maths up to the age of 18, a report for the Conservative Party has said.
It says radical change is needed to give children the mathematical skills needed to succeed in a workplace where numeracy is increasingly important.
The report, by TV presenter Carol Vorderman, said the current system was failing young people.
Almost half of 16-year-olds fail to achieve grade C at GCSE, with just 15% studying maths beyond that level.
This compares to almost all other industrialised countries, the report says, where either all, or nearly all, students study maths to the age of 18.
Ms Vorderman led a "maths task force" to produce the report, which was commissioned by Education Secretary Michael Gove and Prime Minister David Cameron when they were in opposition in 2009.
She said more than 300,000 16-year-olds each year completed their education without enough understanding of maths to function properly in their work or private lives.
She said 24% of economically active adults were "functionally innumerate", and universities and employers complained that school-leavers did not have necessary maths skills.
Ms Vorderman told BBC Radio 4's Today programme that pupils who did not achieve the expected standard - level 4 - in the national curriculum tests known as Sats at age 11 faced a "catastrophe".
Some 90% of them go on to fail to get a C at GCSE, she said.
"If you're on the scrap heap by 11, you will remain mathematically on the scrap heap," she said.
She recommended that the maths Sats, or national curriculum test, be scrapped, as it led schools to narrow their teaching to focus on the tests.
The test brought "no benefit to the children taking it," the report concluded.
Ms Vorderman's team concluded that the GCSE curriculum leans towards advanced topics needed by those who will study maths at A-level, which puts off less gifted pupils.
The former Countdown host, a long-standing advocate of better maths study and teaching, said pupils were being taught trigonometry and algebra when "they can't even calculate a percentage".
The report recommends that the current maths GCSE should be split into two separate exams.
One would offer a higher standard of education in the core areas of the curriculum, such as basic numeracy and personal finance, while the other acted as a preparation for A-level.
The report says all pupils should study maths to 18, but this should not necessarily be in the form of an A-level or AS-level course, but should include a range of options to suit all abilities.
The task force also said that many primary school teachers are not adequately prepared to teach the subject and staff shortages mean a quarter of secondary school pupils are taught by non-specialist maths teachers.
The report calls for better training to improve primary teachers' subject knowledge and confidence; the active encouragement of maths activities outside the daily lesson; and a new assessment for 11-year-olds to replace Sats.
Ms Vorderman, who graduated from Cambridge University with a third class degree in engineering, said: "Mathematics is a critically important subject. It is a language without which the entire global infrastructure is struck dumb.
"This report does not make comfortable reading. It is aspirational but this does not mean making maths harder for everyone; it means making the teaching better and what is taught much more suitable for those who are learning it."
In the face of current financial turmoil, Ms Vorderman said: "Who knows which countries will come out on top in 20 years - is it going to be a country which has a lot of numerate people, or is the one that doesn't bother?"
The government has already said it intends to make maths study compulsory to the age of 18 for students who have not achieved a grade C or above at GCSE.
In June, Mr Gove also said he would like to see the "vast majority" of pupils in England studying maths to the age of 18 within a decade.
He said there were strong arguments for "making certain subjects compulsory for longer".
Mr Gove said Ms Vorderman's report would be of "great help" as the government continued "its drive to equip our children with the skills that they need to compete with their global contemporaries".
"As Carol and her team point out so powerfully, we are falling behind our competitors when it comes to mathematics education."
The Royal Society and Advisory Committee on Mathematics (Acme), which have both raised concerns about maths standards and made similar recommendations, welcomed the report.
Acme called for a "broad set of mathematics qualifications that are designed to meet everyone's needs".
The Confederation of British Industry (CBI) backed the recommendation for maths study to the age of 18.
"Businesses are most concerned about basic levels of numeracy and it's alarming that more than one in five 16-19 year olds are considered functionally innumerate," said Susan Anderson, the body's director for education and skills policy.
But the National Union of Teachers said it was "not entirely sure" why the task group's report was necessary as a full review of the National Curriculum is currently being carried out.
"There is nothing particularly new in the idea of primary school teachers requiring more maths subject knowledge," said general secretary Christine Blower.
"Indeed, the last government looked into it, but a reluctance to match that need with proper funding is the reason nothing ever happens."