A TEACHER at my secondary delighted in starting to call out his daily dose of ''10 mental'' as he strode along the corridor. The A-stream pupils, on the whole, were unfazed by this rude awakening of mathematical sensibilities. But for a few, mental gymnastics induced severe anxiety - the thud of those boots heralded worse horrors to come. Then the ritual humiliation began: a show of hands, starting with 10 out of 10. One soul habitually clocked nul points: me.

For over half a century, I've ducked and weaved to avoid contact with numbers. It does nothing for your self-esteem. I remain as bamboozled by mathematical concepts as dyslexics are by the written word. Armed with a paltry O level arithmetic (passed with private tuition in sixth year at school) accessing the degree course of my choice necessitated an inventive array of passes in obscure ''non-mathematical sciences''. Marriage to a mathematician has proved a rich blessing.

But now people like me (and we include Bob Monkhouse and Lynda La Plante) can come out without shame thanks to mathematician Mahesh Sharma, Professor of Education at Cambridge College, Massachusetts. We are not dumb, he insists, just suffering from dyscalculia, a disorder of the part of the brain used to process numbers. (The term was coined in the 1940s by the neurologist Gerstmann.)

Intrigued by the complexity of mathematical learning problems, Sharma is focusing attention on the condition, building up research and developing teaching methods. ''Classic dyscalculia affects 2% of the school population,'' he says. ''A diagnosis rests on the interaction between the brain's hardware - visual perceptual ability, for instance - and the software like pattern recognition. Dyscalculia and related problems are just as prevalent as linguistic problems like dyslexia.''

Sharma's US Centre For Teaching/Learning Mathematics is linked to a company near Reading run by dyslexia expert Patricia Brazil. Since 1985 Sharma has made annual visits to Berkshire Mathematics, where he presides over teacher-training courses for remedial maths.

Elizabeth MacKenzie, principal teacher at the Dyslexia Institute in Glasgow, attended one of them. She had to work three hours every day with selected children in Berkshire schools. ''Increasingly people turn up at the Institute saying they can't count so I was given a grant to learn from Professor Sharma,'' she recalls.

At the Institute in Glasgow (the only one of its kind in Scotland) MacKenzie has devised a remedial maths course which combines her own training with Sharma's insight. These focus close attention on six key areas: short-term memory; sequencing; laterality (number, unlike reading, doesn't go from left to right); fine motor control; and organisational and audio-visual skills. Confidence with numbers is built up around this infrastructure. Although MacKenzie sees only a couple of pure dyscalculics a year, more than 30% of her dyslexia clients are also dyscalculic to some degree. ''It is a cognitive problem - nothing to do with intelligence or lack of hard work.''

In fact, it affects people like 39-year-old Denise, a married woman from Edinburgh. Denise is incapable of counting out change, of learning tables, of remembering a four-digit number (she can't use a cash dispenser) - yet she graduated BSc with honours in July. ''People don't believe me because I've reached a fairly high educational standard,'' says Denise, who contacted Berkshire Mathematics after seeing a TV interview with Sharma in August.

Always strong on biology and chemistry, Denise started out as a lab technician, discovering too late that the job entailed weekly statistical analysis: ''If someone said 'what's three times 32?' I'd just look blank. Everyone thought I was thick. I became an absolute mess and lost every ounce of confidence. I remember crying at my desk trying to work out dilution factors.''

Unlike many dyscalculics, Denise has confronted her problem since leaving school. She has resat standard grade maths (and failed) but passed two Scotvec maths modules. In the one mathematical section within her BSc she scraped by with 52% thanks to intensive tuition. Denise fears that maths will continue to dog her progress, a worry familiar, too, to Shirley Bwye, a mother in central region. Her nine-year-old son attends one of Scotland's top private schools. His reading age is 12, yet he has trouble telling the time, calculating change from a pound, and so on. His short-term memory is hopeless.

His school has referred him to the Institute For Neurophysiological Psychology in Edinburgh where he attends every six weeks for sound therapy (to help left/right ear dominance) and appropriate physical exercise. In York, with the help of the town's Dyslexia Institute, Rowena Whiting has managed, after a titanic struggle, to secure similar remedial action for her dyscalculic daughter. Twice the 14-year-old has won general merit prizes, yet cannot learn tables, muddles the months of the year, and was a numerical no-hoper. The Whitings spent 18 months battling with the local authority (and latterly an educational tribunal) to have their daughter ''statemented'' for maths - that is, to have her made eligible for several hours a week of personal tuition at school. ''A psychologist said her all-round performance didn't warrant it. It was very confrontational but we got there and now she's making

progress,'' says Mrs Whiting, whose nursing career has also been blighted by the same handicap.

Sharma believes dyscalculia is at least 25 years behind dyslexia. ''In the West, literacy was deemed more important. But with technology more accessible, people are less willing to accept mathematical ineptitude,'' he maintains. He stresses however that dyscalculia is not a clear-cut syndrome - there is no one cause. And before leaping to the conclusion that you have it, consider whether you're simply suffering from poor teaching. Or lack of confidence. Or maths anxiety. All these issues can be addressed by specialist teachers too; Sharma's researchers have devised diagnostic tests which match methodology to mathematical learning personality. ''Some need months, others years. But we have success with over 95%.'' With children, cutting down on computer games is a good start. Develop a child's sequencing and deductive powers with games like Rummikub.

One of the interesting features about dyscalculia is that sufferers tend to exhibit the same traits, ranging from difficulty with spatial orientation (retaining multidigit numbers, reading maps) and sequential activity (following recipes, telling the time) to problems with interpreting codes and patterns. In the preparation of this article I've found myself on common ground with many of the interviewees. For the first time ever, we've all found some comfort in numbers.

n Useful numbers: Berkshire Mathematics (0118 9474864); Dyslexia Institute, Glasgow (0141 334 4549); Solutions for Special Learning Difficulties: Identification Guide (01823 289559); Wandsworth Centre for Developmental Learning Difficulties (0181 8773329).