Abstract
Individual interviews were used to explore 128 seven-year-old children's
understanding of place value, to see how this related to the strategies that they
used to solve written addition problems. Children who understood the place
value of two digit numerals were more successful at solving written addition
problems, but a surprising number of children with face value understanding
could also solve the problems. The variety of strategies (successful and
unsuccessful) that the children used are described, and the implications for
teaching algorithms are discussed.