According to new research number blindness is more common than word blindness.
In a study led by researchers from University College in London, it was found that dyscalculia, a learning disability that leaves sufferers unable to deal with numbers, is more common than its linguistic equivalent, dyslexia.
The research led by Professor Brian Butterworth was carried out in Cuba involving 1,500 school pupils and it revealed that 3 and 6 per cent of children suffer from dyscalculia - compared to between 2.5 and 4.3 per cent of children who suffer from dyslexia.
Butterworth, a professor of cognitive neuroscience, says dyscalculia can badly affect the sufferer because it causes problems with time, money and all sorts of simple calculations needed on a daily basis.
Professor Butterworth says dyscalculia means sufferers have difficulty getting and keeping jobs, have worse health prospects and are more likely to get arrested.
The disability says Professor Butterworth, has nothing to do with how a child is taught, but is the result of children lacking a proper "sense of numbers", which hinders them in maths lessons.
Professor Butterworth says there is increasing evidence that dyscalculia is just as common as dyslexia and yet it is not as widely recognised by teachers, parents, schools, local authorities or governments and there is little help available for individuals.
The Cuban Ministries of Health and Education commissioned a national survey to assess the extent of the problem using a simple screening test developed by Professor Butterworth.
Professor Butterworth says the Cuban authorities recognised dyscalculia was a real and serious problem for a child's future as poor numeracy affects life chances in employment and health and leaves both children and teachers with a sense of failure.
He says it is important the problem is identified early on so that children can be reassured and given extra support.
Experts say children with dyscalculia need specialist teaching and extra support.