The International Mathematical Olympiad annually invites contestants from more than 100 countries to compete in a gruelling two-day test of problem-solving skill.

The battle just to enter the competition is fierce enough, with thousands vying for a place in the world's peak maths contest.

In the end, more than 500 highly trained, tuned and talented young "mathletes" descended on Cape Town for the battle royale.

But it was Alex Gunning who prevailed, the 17-year-old year 11 student from sleepy Glen Waverley winning his second consecutive gold medal.

Not only that, Alex also finished with 42 out of 42 – a perfect seven on all six questions – something never before achieved by an Australian.

Only two other students managed that feat this year – one from China and the other from Taiwan – and they shared the first-place podium with Alex.

"I was obviously quite pleased with the result," Alex said. "I knew a perfect score was a goal worth aiming for, but it didn't know I could do that."

Others did, such as his mother Hannah Cooper and his father Dr James Gunning, a CSIRO mathematician and geophysicist. Alex's four sisters probably had an idea, too.

And of course his teacher Donna Callow, the head of maths at Glen Waverley Secondary College, who identified his prodigious talent back in primary school.

"Alex just has amazing insight into problems," Callow said. "He is so creative and can just see these wonderful connections between different branches of maths."

The wunderkind himself is not sure where his ability comes from, but a big part is the hundreds of hours he spends working on problems, or just pondering them.

Alex walks to school most days and finds his mind drifting to maths as he ambles along, planning solutions and considering new approaches.

"I like to think things through in my head for a while," he said. "I don't directly attack the problem – I ask what results I can get through this or that configuration of points."

In many ways the annual Olympiad is one of the only places where Alex can meet an array of like-minded individuals.

Australia finished 11th overall, just one mark outside the top 10. China, Russia, Ukraine, Canada and the US occupied the top five.

As for the future, Alex likes the idea of studying pure or applied maths at university, in Australia or abroad. But first there is next year's Olympiad to consider.

"I'm hoping next year is harder, you know, for the questions to be more challenging," he said, smiling. "The questions weren't easy as such, but they were manageable."