Adam Spencer describes Lily Serna – the star of the SBS cult shows Letters and Numbers and the currently screening Celebrity Letters and Numbers – as “one of the faces of mathematics in Australia”. In the week when the NSW government announced that mathematics would no longer be a compulsory HSC subject, I asked her to give maths a hard sell.

Fitz: Lily, I want to get to the virtues of maths in the HSC, but first, take me on your own journey to binary calculus heaven, where the sum of the square roots of the other sides always equals Pi (π) to the power of your aunty’s birthday? How did you get into this world?

Lily Serna on Letters and Numbers.Credit: SBS

LS: [Laughing]. I can remember always just loving mathematics and mathematical thinking ever since I was a little girl, growing up in a Palestinian family in Jerusalem. To me, it’s always been solving puzzles. I like the satisfaction of thinking through a problem and arriving at a solution. I have a memory of being very little and driving around with my grandfather and talking about the concept of infinity, how large infinity is – and the fact that you could never reach the end. I remember my mind being blown by that concept. It was a world of wonder to me.

Fitz: Were you blessed with a notably brilliant mathematics teacher?

LS: Yes. I was particularly lucky to have a wonderful maths teacher at Cheltenham Girls High School, Mrs Rosemary Leslie, who fostered my passion. And it was also significant that most, if not all, of my family and extended family studied mathematics at a tertiary level, so I grew up in an environment where mathematics was in our blood and conversation. I never thought it was not a cool thing to study maths.

Lily Serna grew up in a Palestinian family in Jerusalem.

Fitz: I did 4 Unit Maths for the 1979 HSC and got 152/200. I was told that I got 150 for having the courage to do it in the first place and two for signing my name correctly! I’m guessing you got 199 or 200 out of 200 and blitzed it?

LS: [Laughing.] Not always. But I always excelled at it, and I guess that encouraged me to keep going. But I wouldn’t necessarily say I was always the most brilliant person in the class or in the school. I just really loved maths, and then studied applied mathematics at UTS in the finance area, with pure maths subjects, and got a first class honours degree in maths and environmental modelling.

Fitz: So, how did you get the gig on the first Letters and Numbers 14 years ago?