The contents of the Cambridge Mathematics exam are so important that the document is stored in a safe and Whanganui High School is regularly audited.
To prevent the Cambridge International Examination questions being shared, students in three time zones complete them at the same time in November.
WHS students have had the opportunity to do these exams since 2012 and last year, 14 of them took part with much success.
Leading the charge was Ahimsha Saravanapavan who received an overall A on the exam that provides students with an opportunity to gain a wider knowledge of maths.
The A level group is tutored by Christopher Burrows who was thrilled with the results.
"I was really pleased with our top scorer Ahimsha. She was a Year 12 working at Year 13 and she has been great," Burrows said.
"I had another lad who came through and just attended for fun, with no intent to do the exam, just because he knew he needed extra maths for university."
There are three levels of Cambridge Mathematics offered at WHS, which became the examination centre when Whanganui Collegiate School stopped offering it in 2014.
Year 11s have the opportunity to take part in IGCSE classes which are taught by Reka Hermann, the leader of Cambridge Mathematics at Whanganui High School.
Historically the IGCSE course was extracurricular, requiring students to study during lunchtime or after school, but 2019 marks the first year it is part of the timetable.
That's because it's growing in popularity. When the course was first delivered it had eight students, the next year it was 28 and now it averages 20 students a year.
Burrows has been teaching at WHS since 2007 and delivering Cambridge Mathematics since 2013.
He said it was a perk of the job to meet students who have the same passion that he does.
"It's not everyone's cup of tea, but a lot of these kids are really proud of what they do and we need to try to break the stereotype of the general population's opinion of maths.
"They're happy to give up going home early on a Friday and doing extra hours of maths instead. It's challenging and it sets them up for university really well."
Overall A - Ahimsha Saravanapavan; AS level A - Nanea Schurhammer.
Year 11 IGCSE: A* - Sharon Xu; Jeffrey Lin; Jared Turner; Jack Fawthorpe.
A - Leah Aiono; Priyansha Banghia; Mathew Anscombe; AkShima Marwah; Calum Sinclair.
B - Tanisha Rochelle Jones; Gabrielle Sturdee; Connor Hoskin.