Critics say the books are another sign of a nursery rat race that is forcing children into formal education too soon. They believe that "coaching" pre-school children may distort the results of five-year-olds' tests. But publishers say they are simply responding to parental demand and that children find the books fun.
Since last year, all children have been tested when they start school and the Government has just produced a list of goals children will be expected to achieve by the end of their first year at school.
Carol Vorderman, the maths expert on the television show Countdown, joined David Blunkett, the Secretary of State for Education, last week to back Maths Year 2000, which starts in January. She is supporting a series of workbooks, including four for children aged three to five, published by Dorling Kin-dersley. They contain sheets of more than 70 gold stars to be awarded to under-fives who succeed in drawing triangles, writing the words red and green and distinguishing between short, shorter and shortest. The books have extensive notes for parents on how to help children with different mathematical concepts and advice on how to revise topics.
WH Smith and Letts Educational already produce pre-school workbooks and report that sales are rising sharply. Sophie Mitchell, director of publishing at D K Interactive Learning, said: "The sales figures show that the market is ripe for this kind of thing.
"We also used focus groups of children and parents. Children are starting school younger, and most have some kind of nursery education. There is a nursery curriculum and the Government has set desirable outcomes for five-year-olds." She said the books were meant to be fun and give children confidence.
But Liz Pearson, honorary treasurer of Early Education, an early-years pressure group, said: "At this age they should be playing and enjoying books and stories. If parents are going to do this kind of thing with them at home they are not going to be children any more. Children who lead a normal life and have lots of different experiences are going to be just as successful in these tests."
Carol Vorderman said of the Maths Made Easy series, which caters for children aged three to 11: "We want all children to have a good start in life: as a parent I'm particularly aware of that. That's why I'm committed to popularising maths, trying to make it easier for everyone to conquer."