Mathematical ratios: is a competition just for girls a plus or a minus?

For every nine boys in international mathematics competitions, there is just one girl. But critics say a female-only olympiad risks making the division worse

When Lisa Lokteva realised as a child that she was a maths whizz, her grandmother gave her a present. "Here is a book about female mathematicians," her grandmother said. "Read it and learn how bad their lives are."

Now 18, Lokteva is a bronze medallist and the only female member of the Swedish maths team at the International Maths Olympiad (IMO) this year.