Scores and foreits — An intuitive model for integer arithmetic

In introducing pupils to directed numbers, the number line is often used as an intuitive model. The C.S.M.S. project, however, recommended that for the teaching of integer subtraction the number line should be abandoned. Here an alternative model is set up and presented to children. Their response over three lessons is described and their learning is assessed in a post-test. Their response and performance is compared to that of a similar group of children learning through a number line model. The two models are compared from practical and theoretical viewpoints.