I then began to do some examining and became the chief examiner for maths CSE for the London board. In 1994 I was asked by Heinemann to write a maths textbook to accompany the new GCSE syllabus.
I would advise any teacher to do some examining at some point in their career to see what children actually do. You learn such a lot, and I think it makes you a better teacher.
Seeing how children perform in an exam has also helped me write for them: I noticed the lack of working out shown, not writing clearly, not explaining what they were doing. I wanted a clarity of layout and writing in the textbook. I also wanted to give children two ways of looking at a particular question or process, because children see things very differently. Some see things pictorially, some see it as patterns, or remembering steps.
The Impact Maths books are similar in approach to the GCSE book, and we've included more questions at the back than textbooks have had in the past; the thing about maths is you do need to practise the processes to make sure that ideas are retained.
Impact Maths also includes, for the first time, a CD-Rom, with a bank of tests, so that teachers can put together their own material more easily. Maths teachers need something clear and straightforward they can relate to - particularly because so many of them are not maths graduates.
What I enjoy about writing the books is getting to the end product. The royalty cheques help, too, about 5p for every book sold, and the GCSE book has sold about 250,000 copies.
I also like thinking about different ways of explaining a familiar topic and that's probably what got me interested in writing. In all my years of teaching, I've seldom taught the same lesson in the same way; you can always look for a better way of explaining something, that will switch the lights on all round the classroom.
Gareth Cole was talking to Diana Hinds. Impact Maths is reviewed below
Gareth Cole is a senior teacher at Kingsdown school, Swindon, and principal examiner for the London board GCSE. He has written a GCSE maths text book (for Heinemann), and is one of a team of writers on Heinemann's new key stage 3 Impact Maths scheme, Year 7 books are available, and Years 8 and 9 forthcoming.