Richard Dunne loved maths. And he wanted children to love maths, too. Wielding plastic cups, the teacher trainer would explain complex mathematical concepts to primary children, teachers and parents. Their resulting mathematical competence never ceased to thrill him.
Mr Dunne was born in Hertfordshire in January 1944. Growing up in a house with no running water or electricity, he did not consider himself poor; he simply got on with life as he knew it. As a teenager, he dreamed of working in a record or bike shop. But his headteacher persuaded him to go on to further study and he completed a degree in physics and maths at the University of Reading, before training as a teacher.
In 1966, Mr Dunne took a job at a Reading boys' grammar. It was here that the seeds of his distinctive teaching style were sown. Realising that A-level maths pupils did not understand decimals, he reached for a nearby plastic cup and cut it into 10 pieces. This would eventually come to define his method of teaching.
He became head of maths at a Reading comprehensive, and then deputy head at a middle school in Lowestoft. Brought in to revive the curriculum, he encouraged all teachers to introduce his methods. In any subject, he said, you can teach young children abstract ideas.
Not everyone agreed. This always baffled Mr Dunne. He could prove that his methods worked; he simply did not understand why people were unwilling to try them.
Eventually, he moved into teacher training, and in 1988 took up a lectureship at the University of Exeter. He had already written the first version of Maths Makes Sense, his scheme to teach maths concepts such as fractions using sets of plastic cups. But when the national curriculum came out in 1989, his publisher pulled out.
In 1995, Mr Dunne took early retirement, becoming a freelance maths consultant. Maths Makes Sense was finally published in 2007, and he toured schools, demonstrating it for teachers. He also ran parents' demos, watching adults burst into tears as they understood maths for the first time. Indiscriminate in his friendliness, he was remembered by teachers, parents and ancillary staff alike.
This was not, however, reciprocal: he suffered from severe face blindness, and struggled to distinguish even his own daughters. Anxious not to appear rude, however, he developed coping strategies, asking question after question until he had worked out who he was speaking to.
He replied to every email, offering detailed guidance to teachers or parents. Or, indeed, to pupils - he travelled the country, tutoring children who were struggling to understand maths concepts. He did not charge for these sessions: money concerned him far less than the joy of watching children grasp mathematical concepts.
Mr Dunne died on 3 March. He is survived by his wife, Carrie, and four children - Nicola, Sarah, Matthew and Rebecca.