These days, the 14-year-old from Bilgola Plateau is one of the youngest HSC students in NSW, and this month he'll sit two exams - Mathematics Extension 1 and 2.

Numbers and maths have always just made sense for the Year 9 Barrenjoey High School student, on Sydney's northern beaches, who especially loves algebra and calculus. He used to like trigonometry, but not so much any more.

The Brondum household is busy on the Friday afternoon we visited to speak to maths whiz Griff. School's just finished and older brother Lorcan, 16, breezes into the lounge room mid way through the interview to say hello.

"They're both so different, the boys," Mrs Brondum said. "Lorcan's not maths at all, he's completely artistic. He's a finalist in the northern beaches art prize [2021 Northern Beaches Environmental Art and Design Prize]."

In an attempt to distract the family's dog Disco from our feet as we talk, the boys' father John calls her outside to play ball. Amid this scene of domestic bliss, Mrs Brondum explains there was no "ah-ha" moment of realising that their son had a gift for maths. The realisation came gradually.

IN OTHER NEWS:

"There were things like measuring everything in the house, he was obsessed with big numbers like Google and binary," Mrs Brondum said. "He was always doing maths stuff and he taught himself how to do it, I was always finding bits of paper around with stuff all over it."

But it wasn't until she discovered a list comparing a bright child to a gifted learner that she really realised.

As outlined in Psychology Today, a bright, above-average student is likely to get As. They memorise well, comprehend at a high level, absorb information and complete their work. A gifted learner, on the other hand, comprehends the nuances of the subject's material in a more complex, in-depth manner. Where the bright child accepts and readily retains information about the topic, the gifted learner manipulates that information in order to draw unique inferences.

For Griff, the realisation came a couple of years later. "I probably realised when I was eight when I first went to high school for my maths, when I was first around people that were older than me doing maths," he said.

"For every question that they had to do out of the textbook, they had to write down the question. I just started writing in the textbook because I could just answer it in one line, and they had to write out the question and then three lines of working."

The journey to becoming a 14-year-old HSC student has been tough at times for the entire family.

"Advocating for these kids can be extremely arduous and Griff is what you call 'twice exceptional', he's gifted with dysgraphia as a disability," Mrs Brondum said. Dysgraphia is difficulty with spelling and written expression, and Griff often needs more time to be able to produce written work than other children his age.

Kindergarten was tough. He felt out of place as soon as he started and was bullied. Mrs Brondum left her job as a freelance writer and editor to home chool Griff.

Three years later he started at Mona Vale Public School and then enrolled in Year 9 and 10 maths via distance education.

"Maths just seems obvious to me, more than other things," Griff said. "I like it more than other kids would, most other people hate it, most other people in my grade hate it.

"There's specific long equations that can be very satisfying when you finish doing them. When everything that's very complicated just adds up to a single whole number. I just like the patterns."

The ability to recognise patterns and Griff's visual-spatial processing helped him win countless chess trophies when he was younger. The trophies, along with a front page story about the chess prodigy when he was six years old, still adorn the entry foyer of the family's Bilgola Plateau home.

These days, Griff said it's not only Maths Extension 2 that challenges him, but also the music of German composer Johann Bach. The family's piano takes pride of place in the lounge room, just behind Griff as he explains he first learnt to play when he was six. He's now playing at Suzuki level nine.

While Griff might have had a tough start to his formal education, Mrs Brondum is quick to praise public education overall.

"The school here [Barrenjoey] was fantastic and Mona Vale were fantastic," she said. "A lot of people don't realise that public schools are able to cater for this kind of student, you just have to find the right one and talk to the right people. Learning support at the school is absolutely fantastic, I can't tell you how helpful they've been."

Griff hopes to study maths at university, and maybe physics a little later on, but right now he's just focused on finishing the year and those two HSC exams.

He's not nervous or worried, after all those exams will be in his favourite subject.

"The only good exams are maths exams," he said. "I'd be fine if all assignments were just in maths."

Youngest and oldest students

Top five given names of this year's HSC students

Top five family names of this year's HSC students