Jensen Au Yeung was doing basic maths by 2 and algebra by 3. Now aged 10, the Auckland boy is making friends with teenagers after skipping five grades at school.
Jensen, who loves Lego, his dog Fluffy, and also plays representative football, moved to ACG Senior College last month and is the youngest (and smallest) "by miles".
But he says he likes it anyway.
"Here it's 100 per cent at my level," Jensen said. "It was a big jump with maths because there's papers in statistics and lots to learn, and there's quite a lot of homework, but that's okay."
Jensen's parents, who also have a 6-year-old daughter, noticed he may have special skills when he was 2, as he could pick different countries on a map and do complex sums involving negative numbers.
He was measured in the top 0.1 percentile when tested by a psychologist. He plays piano, takes karate and can hold an adult conversation. He is particularly gifted in mathematics and has already passed Cambridge IGCSE Math exam, scoring 98 per cent. This year he is studying chemistry, physics, maths and English alongside 16- and 17-year-olds.
Despite his family's initial reservations, Jensen says the older kids "aren't scary" and he doesn't feel like the odd one out - despite having an extra-tall chair to reach the desks in the science lab.
"I think about it a little bit," he said. "But it's hard not knowing you're special, because you don't know any different."
Principal Kathy Parker said she isn't usually an advocate of accelerating students ahead of their age group, but Jensen's case was an exception.
"He's such a well-rounded, intelligent child who doesn't fit a conventional system," she said.
Mrs Parker said she was keeping a close eye on him, however, as she didn't want him to be lonely. "But so far he's doing really well."
Head of the the New Zealand Association for Gifted Children, Rose Blackett, said it was rare for children to accelerate through so many grades.
"It has to be down to an individual basis," she said. " Not all children could safely skip ahead, and not all would want to. While some would be good at one particular area - often maths - they would struggle with literacy or social skills."