"It's for the whole country so I thought for sure someone else would get 100 per cent."
Ex-WHHS student and brother Eric did the same exam two years prior. Jason beat him, but he's not rubbing it in. "We're not that competitive," he said.
Jason was born in Korea and his family moved to New Zealand when he was 8. He attended Lynmore Primary School and John Paul College before Western Heights High School.
Cambridge exams (or Cambridge International Examinations) are held twice a year in June and November. They offer examinations and qualifications to 10,000 schools in more than 160 countries. Last year more than a million students sat Cambridge examinations.
Jason found out his top result in January for the IGCSE math without course work exam and accepted his certificate at the Outstanding Cambridge Learners Awards in Auckland last month, which included $100.
Jason has not decided on his future career and is keeping his options open.
"But if I keep getting good results it will be something involving maths," he said.
If he decided to study overseas, the Cambridge exams would help make the transition easier, he said.