The interest in Phase 1 of the study lay in the ability of the children to abstract a sum from a real life situation to work it out and then to re‐apply the answer back to the situation and also in problems with two‐digit addition and subtraction. Results revealed that the children did not reapply their answers back to the situation. They were competent in addition, but not in subtraction. The latter was subjected to further investigation in Phase 2. It was found that children did realize that change should result from a shopping situation. However they were able to use neither an informal strategy of shopping with coins, a formal one of double decomposition nor a calculator with any degree of accuracy. Nor did they realize that they could use one strategy to cross‐check another.