Almost half of the adults in England have a poor understanding of maths, according to a new charity.
National Numeracy has found that 17 million people in the country struggle with the subject.
Many of them have an understanding of numeracy equivalent to that of a primary school pupil.
The number of innumerate adults in England has grown by up to two million in eight years and there are fears this is having a major effect on the individuals and the UK economy.
Chris Humphries, the chair of National Numeracy, told Sky News: "That's a scary figure, because what it means is they often can't understand deductions on their payslip, they often can't calculate or give change.
"They have problems with timetables, they are certainly going to have problems with tax and even with interpreting graphs, charts and metres that are necessary
for their jobs."
He added: "It does matter, poor numeracy seriously blights an individual's life chances.
"Young people with poor numeracy are twice as likely to be excluded from school, we know adults with poor numeracy are twice as likely to be unemployed."
"It is simply inexcusable for anyone to say 'I can't do maths'. It's a peculiarly British disease which we aim to eradicate.
"It doesn't happen in other parts of the world and it's hitting our international competitiveness. With encouragement and good teaching, everyone can improve their numeracy."
Unlike poor levels of literacy, it seems many people are not even concerned about their lack of basic numeracy. Only 56% of those questioned were embarrassed about their poor maths skills.
The charity is hoping to address the problem, encouraging those of all ages to improve their poor levels of numeracy.
Jan Dawson, who teaches maths to adults at Bournville College in Birmingham, is one of those trying to do something about the problem.
She told Sky News many are turned off maths while still at school.
"Invariably they're quite anxious about maths. They've had bad memories of maths from when they were at school but very often they will leave here and say that was great I understand, the penny has dropped," she said.
Many of the mature students in her class have decided to brush up on their maths after realising their lack of knowledge has held them back.
Louise Galvin has a 13-year-old son and until recently she would worry when he asked for help with his maths homework.
"My son's got autism but he's very good at maths. Sometimes he comes home from school and I find his homework really shocking because it's tough for a 13-year-old, but now I can help him with it because I understand it better," she said.
Those involved in the new campaign believe some people even see a lack of ability at maths as a "badge of honour".
Speaking on Sky News television personality Johnny Ball, famous for popularising maths and science in TV programmes in the 70s and 80s, said the curriculum and the way maths was being taught were letting children down.
He said: "Teaching standards are not really strong enough in so many schools."
International studies show that the UK is lagging behind other nations when it comes to the subject.
In 2006, it was ranked 17th out of 30 developed nations in terms of the proportion of people with low or no qualifications.
Some 35% were considered to be at that level - double the number of countries such as the United States, Canada, Germany and Sweden.