It affects one in 20 people, can undermine their confidence and frequently leads to the embarrassment of counting on one's fingers. Yet the biological inability to recognise numbers is still not seen for the medical problem that it is, experts said.
Just as dyslexia is a learning disability that inhibits the recognition of words and sentences, dyscalculia is a learning problem associated with the inability to handle numbers. But nobody is taking it seriously even though between 5 and 7 per cent of children suffer from the handicap of not being able to do sums easily, scientists said.
Professor Brian Butterworth, a neuroscientist at University College London, has called for a greater awareness of a problem that he believes is blighting the lives of a significant minority of people who cannot do simple arithmetic and are not necessarily aware of why they suffer from a problem that has dogged them since childhood.
"Broadly speaking, people in this country think literacy is more important than numeracy and it's OK to say 'I'm bad at maths' and not OK to say 'I'm bad at grammar, spelling and pronouncing words'," Professor Butterworth said. "Dyscalculia is at least as much of a handicap for individuals as dyslexia and a very heavy burden on the state, with the estimated costs in the UK of low numeracy standing at £2.4bn (NZ$4.8bn)," he added.
Experts believe the status of dyscalculia as the poor relation to dyslexia is undermining efforts to address the problem with greater public awareness and better education. Even though they believe that dyscalculia is largely biological, and can be inherited, they also believe it is possible to correct it to some extent if it is identified early enough.
"There isn't much official recognition of dyscalculia and I think there ought to be. Parents should be more aware that if their children suffer from dyscalculia it does not mean they are stupid," Professor Butterworth said.
Dyscalculics often devise elaborate tricks to handle numbers as a way of overcoming their handicap, but they can still show wildly inaccurate attitude to figures, such as estimating the height of a room to be hundreds of feet.
A study in the journal Science led by Professor Butterworth says that apart from the wider impact on society and the economy, dyscalculia and low numeracy imparts huge costs on individuals, more so than the impact of low literacy on individuals.
"They earn less, spend less, are more likely to be sick, are more likely to be in trouble with the law, and need more help in school ... There is an urgent need to help failing learners achieve a level of numeracy at which they can function adequately in the modern workplace," the study says.
Several studies have shown that dyscalculia has a significant inherited component. Sufferers are likely to have siblings with the same problem, and it is more commonly shared between pairs of genetically identical twins than non-identical twins.
Other studies have indicated that the problem is related to the development of the brain either during pregnancy or in the first years of childhood. But early intervention with the right approach in teaching can help, said Professor Diana Laurillard of UCL's Centre for Educational Neuroscience.
"Just because dyscalculia is inherited it does not mean that there is nothing that can be done about it. As with dyslexia, specialised teaching can help," Professor Laurillard said.
"Results from neuroscience and developmental psychology tell us that dyscalculic learners need to practise far more number-manipulation tasks than mainstream learners," she said.