When Susan Wall asks her colleagues whether they think she is a workaholic, the reply is a unanimous and resounding "Yes! Yes!"
Ms Wall returned to teaching 10 years ago after raising her three children.
Now, the 54-year-old is head of maths at Wilberforce sixth-form college in Hull.
She works from 8am until 5pm at school, returning home to devote three more hours to her job.
"I enjoy it," she said. "I like thinking of new ideas and doing things for students."
In her spare time, she runs extra-curricular maths groups. She was awarded a Gatsby fellowship in 2001.
Even at home, her thoughts often return to the classroom: "I do a lot of gardening, and that's good thinking time. Everywhere you are, something sparks a little idea.
"Maths was always fun to think about and talk about with my sons. Whatever we were doing, maths came into the conversation."
When she is not teaching, she learns. She plays the cello and has a masters degree. She regularly updates her ICT skills. Six years ago she decided to learn the saxophone and now plays in a band.
"There's always new stuff to try out," she said. "You never stop teaching because you never actually switch off.
"It's just that sometimes other things come to the fore."