Julia Melvin passed her numeracy skills test at the sixth attempt.
The 45-year-old, who did her postgraduate certificate in education at London university's Goldsmiths College, was distraught after failing - but determined to succeed.
"It just meant I had to learn my times tables," said Ms Melvin, who now teaches design and technology teacher at Pimlico school in London.
"We were told quite clearly by our tutors to get the skills tests over with, but when you are on the learning curve of a PGCE you don't want to take on any more.
"I had managed to avoid numeracy my whole life by using machines or asking other people. It came to a point where I had to get over my mathematical demons and knuckle down and do it."
Ms Melvin was born in the UK but grew up in Australia. She left school at 15, but quickly tired of her factory job and returned to college to learn graphic design. She went on to run her own business and did a degree in communications at Sydney University of Technology before returning to England to work as an interactive television designer.
She said: "I didn't really need maths. I kind of stopped at long division and thought 'I don't like this, I just don't want to go there'.
"I've always been very good at art and maths just seemed unnecessary.
"Then I became a mum and decided I wanted a career which was more closely related to family life.
"I did ask one of the assistants at the Victoria test centre in London what the record number of tries for the skills test was. It was 27 times."