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Outstanding ACG Parnell mathematicians represent New Zealand at the IMO

Having one student selected for the six-person International Mathematics Olympiad team is an extremely noteworthy accomplishment. However, this year, two outstanding ACG Parnell College mathematicians – Brain Zhao and Eric Liang – were chosen to represent New Zealand at this highly competitive event.
Talented ACG Parnell mathematicians take on the IMO

Universally regarded as the most prestigious – and the most challenging – mathematics event for pre-university students, the International Mathematical Olympiad (IMO) is the world championship of high school competition. 

The annual tournament brings together the best of the best, with over 100 countries participating in the intense two-day contest. Accordingly, the selection process is rigorous, and dozens of potential candidates are winnowed down to a six-person squad representing each nation.

In 2022, two ACG Parnell College students, Brian Zhao and Eric Liang were selected for the New Zealand team. They enjoyed a phenomenal experience at the competition in Oslo and have shared their thoughts and impressions below.

“The 63rd International Mathematical Olympiad was held in Oslo earlier this year. It was truly exciting to travel so far from home and be among so many talented mathematicians after two years of online IMO due to the Covid-19 pandemic.

“The selection process is very involved and starts even before the previous year’s IMO has been completed, with Round One of the New Zealand Mathematical Olympiad occurring in July. From there, candidates go through four stages of competitions with increasing difficulty levels, and only the top performers can qualify for the next stage. 

“Selected candidates will also attend lectures during the January camp and squad and team preparation sessions, although they are expected to conduct most of the training themselves. 

NZMO1 Open to all students Jul One month-long take-home exam with eight questions
NZMO2 Around 100 participants Mid-Sept Three-hour long exam with five questions
January camp Around 25 participants Early Jan Week-long residential camp with lectures + three squad selection tests
NZIMO squad Around 12 participants Jan-Apr Eight training sessions, plus three international competitions (BMO, AMO, APMO)
NZIMO team 6 participants Apr-Jul Eight training sessions, plus the IMO in Jul

“Our journey began as, accompanied by four other fellow members as well as our Team Leader, Deputy and Manager, we boarded the Oslo-bound plane to battle it out with countries from all over the world.

“Upon arrival in Norway, we had around a week to adjust for jetlag and do our final preparations for the competition. Our training leading up to the competition mainly consisted of three major mock exams, two of which were sat with the Dutch (Netherlands) team in a joint-training session.

“Then the official IMO competition began, and we faced two very challenging days. Although we didn’t perform at the level we had hoped, it was still an incredibly valuable experience which provided the following benefits.

  • Solving intriguing problems: if you enjoy solving complex maths problems, you should aim to compete in the IMO.
  • Improving mathematical abilities: the proof-writing skills you develop are very useful for university-level maths.
  • Developing friendships: the contest lasts two days, which means you will have plenty of time to socialise with people from across the world. 
  • Impressing others: the IMO is universally regarded as the most complicated and demanding secondary school contest, even compared to the other science Olympiads. Simply participating improves your chance of getting into good universities dramatically. 

“Additionally, we also have the following advice for both ourselves and whoever should follow in our IMO footsteps.

  • Do. More. Practice. 
  • Be patient. It is perfectly normal to consider a question for quite some time as you formulate how to answer it.
  • Justify every step; don’t just write an answer. 
  • Write down everything that you can think of in your rough work. Then write up a clean solution after you have solved the problem. Submit both the solution and the rough work. 
  • Geometry: draw multiple large, detailed, to-scale diagrams. Make conjectures based on your diagram and prove your conjectures. Repeat as required.
  • Combinatorics: try small cases; find patterns; prove patterns; rinse and repeat. 
  • Functional equations and polynomials: make substitutions, a lot of them. 
  • Read Problem Solving Tactics – Australian Maths Trust Shop (

“Overall, the IMO was a great opportunity, and we felt fortunate to travel to Norway and compete against other international teams. We would definitely recommend it to anyone looking to extend themselves in an exciting, inspiring and thought-provoking environment. You’ll learn a lot and have an amazing time in the process.”


Given that ACG Parnell teams were crowned champions of both the Year 7 and Year 8 divisions at this year’s Auckland schools’ MATHEX Competition, we have high hopes that the next cohort of young mathematicians will aspire to reach the very high benchmark set by Brian and Eric.