Making raspberry jam, playing with grandchildren and watching a spider swing down from the ceiling were all valuable maths lessons, Doug French believed.
For the former president of the Mathematical Association, who died this month, nothing was unrelated to maths. Anything and everything could be turned into a mathematical learning opportunity.
Mr French was born in 1941. His father had enlisted to fight in the Second World War, and father and son did not meet for another two years. After the war, the family moved to west London, where he became fascinated with maths and went on to study the subject at Bristol University.
While there, he volunteered with a local Scout troop, helping to run a residential camp for children with special needs, an experience that encouraged him to pursue a career in teaching. It was also where he met Julia, a volunteer with the local Guide company. She was a history student who struggled with calculus and geometry. But the two found common ground and married in 1966.
After graduation, Mr French volunteered for a year as a teacher in Nigeria. This experience cemented his decision to work full-time with children. On returning to the UK, he enrolled on a PGCE at Leicester University.
His first teaching job was in a comprehensive in Warwickshire. But, after only three years, he was appointed head of maths at Beacon School in Sussex. He stayed in this job for the next 19 years.
Mr French thrived on communicating his love of maths to pupils. A shy man, he lost his inhibitions on entering the classroom. Above all, he wanted to make maths memorable. For example, he would teach Pythagoras' theorem by asking pupils to imagine a spider dropping from the corner of the classroom on to his nose.
Everything was a potential learning opportunity. The way his garage door opened became an A-level question; a children's play-dome on holiday became a geometry lesson.
He and Julia had two children, Linda and Mark. Maths became a part of their lives, too: when Linda started primary school, she stumped teachers by telling them that fingers were for counting with.
Mr French had no ambitions to become a head or deputy head - the joy of the job was in the classroom. But he came to realise that he could influence more pupils if he trained other teachers, so he took a post in Hull University's education department.
In the classroom, he had emphasised the importance of mental agility, and this continued in the lecture hall. When interviewing potential trainees, he would ask them to divide four by 0.8. Many were frightened by the question. But, said Mr French, such lack of confidence is often the biggest obstacle to pupils' success in maths.
Early in his career, he had joined the Mathematical Association. Eager to improve the delivery of maths, he joined its teaching committee and held regular meetings with government officials. He campaigned against a centralised maths curriculum, as he felt teachers should be allowed to decide what was best for their pupils.
In 2006, he became president of the association. He later retired early from Hull so he could dedicate himself to the job.
Even in retirement, Mr French lived maths. Playing with his grandchildren, he would roll pots back and forth across the carpet, fascinated by the mathematics of their movements. And hours spent gardening allowed him to develop a mathematical puzzle that involved making raspberry jam.
He also found time to return to Africa. He and Julia visited a school in Zambia and, back in England, he investigated the possibility of sending over maths textbooks and resources. Shortly afterwards, he was diagnosed with pancreatic cancer and was dead within a year.
Doug French is survived by his wife, their two children and four grandchildren.