Derek, have you always been enthusiastic about mathematics?
At school I was fairly neutral about mathematics until I did the subject at A-level. That’s when it really took off for me. I just loved it and, to be honest, I found it very easy – because I had good teachers who helped me to see the patterns in maths and to understand the underlying principles. I got a place to read mathematics at Oxford, but I rather went off the subject there – mainly because it was so badly taught by Oxford mathematics professors who weren’t really interested in teaching! And, of course, there were lots of other exciting things to learn about and to do at university!

So, how did you get into teaching?
I grew up on a council estate in North Kensington, in London, in a very working-class family. The only professional people I had ever met were my teachers and our family doctor! So, really, I didn’t have much of a clue when it came to thinking about a career! But I did always fancy the idea of being a teacher and my university experience made me convinced that I could do better than the people trying to teach me! As it happens, it was absolutely the right choice for me. Over the years, I have taught mathematics to all ages from foundation stage to university level, and I just find that it can be the most rewarding job in the world. There’s nothing quite like the excitement of engaging with someone else’s learning and seeing the light suddenly switching on!

How did you get into primary mathematics education?
I started out as a secondary mathematics teacher, four years in Nairobi and then three years as head of department in a grammar school in what is now Cumbria. I was then appointed as a mathematics lecturer at Keswick Hall College of Education in Norwich. My main responsibilities were to teach degree level mathematics to the students specialising in this subject. But, to my surprise, the College also expected me to teach mathematics curriculum courses to their primary trainees! All too aware of my total ignorance about primary teaching, I immediately arranged to teach for a couple of months in a primary school in London, where my brother was the head. Thereafter I took every opportunity I could to teach and research in this age range, and gradually over the years it became my personal area of expertise. By the time I was appointed at the University of East Anglia, in 1981, I had established a niche for myself as a mathematician working in the primary field.

How did the teacher become an author?
At the stage when our two daughters were a severe drain on our financial resources, I took on some part-time work for the Open University, as a tutor for various mathematics courses. Out of the blue I was invited to write two numeracy units for the OU’s Technology foundation course – and these were actually my first publications. But what really got me into writing was the experience of having just 12 weeks’ leave to write up my PhD thesis in 1984! Writing full-time day after day to meet a series of self-imposed targets – I found this to be something I could do and something I really enjoyed. So, when Anne Cockburn approached me a couple of years later with an idea for writing a research-based, but practical book together, I jumped at it. Haylock and Cockburn, Understanding Early Years Mathematics, was published in 1989.

What about the connection with SAGE Publications?
I’ve been very lucky with my publishers. Understanding Early Years Mathematics was published by Paul Chapman Publishing, a small publishing company – and was well received. This encouraged me to go on to write another research-based, practical book: Teaching Mathematics to Low Attainers, 8–12, which came out in 1991. Then in 1995, Paul Chapman Publishing published the book which, to my surprise, turned out to be the book that everyone was looking for in primary mathematics education: Mathematics Explained for Primary Teachers. SAGE Publications, a much larger company with many more resources, took over Paul Chapman (and me) in 1998, and since then they have been the publishers of all my education books – new books, new editions, edited works, and so on. SAGE looks after me very well – and produces lovely-looking books!

What apart from mathematics and teaching?
First and foremost, I am a committed Christian. I am an elder in a Free Church in Norwich, where I coordinate the music in worship. The other big thing in my life is my family – especially my three grandsons, who are a good source of occasional illustrations of children’s engagement with mathematics in my books! Music is a big part of my life. As well as listening to music (strictly in the classical tradition!), I play the trumpet (Norwich Philharmonic), and do a lot of arranging, conducting and some composition. I used to write a lot of Christian drama (seven books published by Church House Publishing) and composed a Christmas musical for schools (also published by CHP). I am the Chairman of the Directors of a charity, the Dohnavur Fellowship UK, supporting a Christian orphanage, schools and hospital in Tamil Nadu, India. Then I am fanatical about cricket, Norwich, the Norfolk countryside, holidays in France, my wife’s cooking, reading, walking (quickly) and cycling (slowly). Is that enough?

What are your current professional commitments?
Thanks to a steady income from royalties, I was able to take early retirement from UEA in 2002. Since then I have focused on consultancy work and writing. Much of the last year has been taken up doing the fourth edition of Mathematics Explained and the companion student workbook. I am also involved in writing material for gifted pupils in mathematics for a project based at Leeds University. I am a consultant to the Training and Development Agency for Schools, developing, supporting and monitoring the Student Associates Scheme. And for a number of years I had various consultancy and advisory roles for the Qualifications and Curriculum Development Agency, related to the primary mathematics curriculum and national tests in mathematics.

Why do you think Mathematics Explained has been so successful?
Four reasons, I would say. (1) It’s completely rooted in my years of experience of working with primary trainee teachers and based on what they told me about their attitudes to mathematics and things they felt they did not really understand. (2) It is realistic and reassuring about the anxieties about maths that many of these trainees have and their need to feel confident with the material they have to teach to children.  (3) It relates the mathematical content to learning and teaching in the classroom. (4) Feedback from those who have used the book indicates that they find the writing clear and accessible – and even occasionally amusing! As I always say, when asked about this book, all I do, really, is to explain simple things simply.