When Cheryl was a child, she wanted to be a concert pianist. She started lessons when she was 8. Her first piano teacher was a family friend called Jean Skennerton who was a talented and enthusiastic teacher who expected a lot of her students. Each Wednesday, Jean’s students went to her house after school to do theory work and then had a percussion band session. Cheryl loved the collaboration of group work. Music and movement helped her understand rhythm and it made her feel good. It also helped her shyness when she performed in public because each time, it got easier.

At school, Cheryl was also interested in maths, but there were certain things that confused her sense of logic. Before Year 2, children weren’t allowed to do negative numbers which meant that there was no mathematical answer if you subtracted five from three. She felt a huge sense of relief once negative numbers were taught.

Cheryl’s dad worked in a bank, so the family moved towns every time he changed branches. Maths was easy at different schools because the curriculum was consistent. But not all teachers were as nurturing. In Year 3, Cheryl’s Maths teacher was an old man who wasn’t very nice. When she got chickenpox and didn’t do well in a mental maths test after two weeks off sick, she and others who’d done badly had to stand on their ‘forms’ – long seats without backs which were the seats for four students. She found this humiliating. She was upset and angry because the chickenpox wasn’t her fault. In a strange way though, it made her try harder, so it never happened again.

When Cheryl was eleven, television (black and white only) reached the country town where she was living. Her family did not get their own TV set for many months, but she could sometimes watch TV programs after school at a neighbour’s house. Her favourite was a TV program about science with Professor Julius Sumner Miller. The professor would stand behind a lab bench and perform simple experiments for kids. He became rather famous for his question: Why is it so? Even though it sounded a bit funny, the question was important. Always ask why. Cheryl loved the show and it made her want to study science.

When she finished school, Cheryl wanted to continue her studies, but studying wasn’t an automatic thing in her family. Both of her parents had left school when they were 13 or 14, and the only person in her family who had been to university was her uncle 2000 km away. In those days, many children left school early to go into jobs that didn’t require further study.

Girls mostly learned secretarial skills like typing and bookkeeping. Cheryl and her mum visited a government vocational guidance officer who told her she should be a nurse or a teacher at primary school. He said, ‘Girls don’t do maths. They don’t pass.’ He had seen it before; the girls tried and came back and told him they failed. And even if they did pass, there were no jobs for women in maths.

It turned out the man had no idea.

Cheryl was upset and angry, but her mum took action. She found out that the university had an office where students could get advice on courses. Cheryl went there and was told she could even do pure and applied maths and physics at Honours level. And that was what she did. It was scary and a lot of work, but she felt excited to be there and loved studying.

Cheryl’s last three years at secondary school had been in all-girls classes, but when she got to university, she noticed something about the gender balance of the classes. There were hundreds in the mainstream maths and physics classes, but in the Honours maths stream, there were just 80 people – 70 boys and ten girls. After a few months they had their first exam, and there were 33 people left, four of them girls. At the beginning of second year, there were twenty people, and only one of them was a girl. It was Cheryl. In her advanced physics class, there was one other girl. Cheryl found it a bit lonely, but ultimately, had to fit in and was friendly with the whole class. They all worked together in a big common room and they all spent a lot of time together. By fourth year, there were only eight left in the Honours stream and Cheryl was still there. It was difficult and high pressured.

A big moment for Cheryl was when she got a summer scholarship to the Australian National University in Canberra. While she was there, she saw mathematicians doing research projects and she got to do one of her own and publish a paper on it. For her research project Cheryl was given an equation and had to find a solution for it. A professor helped her to start but it was up to her to try and find the answers. She felt the beauty and excitement in it.

When she graduated from her Honours degree, Cheryl received the University Medal for Mathematics. She won a scholarship to Oxford to do her PhD. At Oxford, she discovered her love of symmetry. From the primary school, where symmetry meant folding things in half along a dotted line, symmetry at uni became a way of describing and classifying things. One example was crystals. The differences between them came down to exactly what kinds of symmetries their structures have.

Once Cheryl finished her PhD, she worked at universities in Australia and in the United States. Finally, she settled into a position at the University of Western Australia.

About ten years into her career there was a huge breakthrough called the Classification of Finite Simple Groups. It changed everything to do with symmetry in mathematics, and became knowns as ‘one of the outstanding achievement of modern mathematics’. Through Cheryl’s whole career she has worked to understand the impact of this classification. Her ongoing focus is to make digital computers compute really quickly. Now, she is working on networks and graphs and working out how to use this powerful tool of classification to make superfast programs on computers to work with symmetry. These exciting projects will keep her busy for a long time to come.

Cheryl Praeger is Emeritus Professor of Mathematics, retiring in 2017 after 40 years’ service to the University of Western Australia. She now focuses on research and research supervision in Group Theory and Combinatorics, in her role as Senior Honorary Research Fellow. Professor Praeger has won many distinguished awards, recognising her as one of Australia’s leading mathematicians. She was appointed a Companion of the Order of Australia for ‘eminent service to mathematics, and to tertiary education, as a leading academic and researcher, to international organisations, and as a champion of women in STEM careers’.

Aside from the resources that Maths teachers provide in classrooms, Professor Cheryl Praeger recommends that you get involved with Australian Maths Trust programs. They have a sandpit playing area and a new online tool called Problemo where you can solve problems with your friends.

Since Professor Julius Sumner Miller made such a big impact on Cheryl as a child, you can find some of his old TV Science shows on YouTube. Here’s one: https://www.youtube.com/watch?v=RUgJUcJ2Xxc