This is a report of a study of the representations and strategies for subtraction, used by a sample of 55 children in years 1, 2 and 3 in three suburban schools in low, medium and high socio-economic areas of Brisbane. Each child was interviewed and videotaped individually early and late in the year. In order to determine what representations and strategies they would choose to use they were presented with operations represented in symbols and asked to explain their procedures as they worked. The teachers were also interviewed to determine the representations that they were introducing. The general development sequence was from use of objects, to use of counting to mental calculations using knowledge of number facts and place value. Written algorithms, with or without concrete materials, were used very little despite the fact that they were being taught in years 2 and 3. The results are discussed from the perspective of the demand that the procedures make on children's information processing capacity and the possibility that some of the difficulties occur because teachers introduce procedures that are recommended in curriculum documents, without being aware of the cognitive load that they impose.