Carol Vorderman, the former co-host of Channel 4 gameshow Countdown, is to head a maths task force for David Cameron, the Conservatives have said.
She will assess teaching methods in England, how to tackle the "fear" of maths and if tests have got easier.
A package of proposals aimed at improving numeracy is to be unveiled by the Conservative leader later.
The government said England's performance had improved in international league tables recently.
Ms Vorderman said that in the last 10 years 3.5m children had finished school without a basic maths qualification.
'Passion for maths'
The TV presenter, who describes maths as her "passion", will visit schools and hold discussions with experts and parents.
Speaking ahead of the launch, Ms Vorderman said: "Maths is critically important to the future of this country but Britain is falling behind the best performing countries.
"In the last decade, 3.5 million children have left school without a basic qualification in maths, a shocking statistic.
There is no question that Britain has developed a fear of the subject and it is time to break that cycle
"If they are to get the best jobs in the future and Britain is to emerge stronger from the recession we have little choice but to sort maths out now.
"There are many centres of excellence and many fabulous teachers but help is needed for the children being failed.
"Maths is my passion, and there is no question that Britain has developed a fear of the subject and it is time to break that cycle."
At the launch, Mr Cameron will draw attention to figures that show it is the poorest children who are doing least well at the subject.
Of pupils who received free school meals, about 60% - 44,368 - gained a D grade or below at GCSE maths last year.
By comparison, information from parliamentary questions revealed only 3,312 achieved an A or A*.
There is some surprise that Ms Vorderman is fronting the Tory maths review, because she took part in one the government commissioned, which reported less than a year ago, and endorsed its recommendations - which are now being implemented.
She said in June: "I am thrilled that at long last an official body is raising the spectre of our negative cultural attitude to maths, particularly in the media."
Schools Minister Jim Knight said the picture in maths was a positive one.
"The latest major international study last year showed that we are leading Europe in maths and have risen 11 places in world league tables since 2003 to 7th place."
When it came to the number of young people getting five higher level GCSEs including maths and English, the gap between the poorest and the rest was narrowing year on year, Mr Knight added.
"But we want to go further and get more young people to enjoy and master maths.
"That's why we are implementing the recommendations of the review by the leading maths academic Sir Peter Williams including having a specialist maths teacher in every primary school."
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