This study aims at determining the structure of the representation constructed by
adults to solve multiple-step arithmetic word problems. We show that this structure
is isomorphic to the structure of the situation described in the text of the problem.
In effect, dynamic problems, which describe sequential events, are more likely to be
solved by sequential strategies than are static problems. In other words, the order of
succession of subgoals reached by individuals for the resolution is determined by
the order of succession of subgoals explicitly described in the text of the problem.
However, an alternative mental representation is constructed by low span
individuals when its cognitive cost is not too high and, therefore, certain static
problems are solved by a sequential strategy as well. We conclude that the
probability of the construction of an alternative representation to the one induced
by the text of the problem depends on its cost and the relative amount of cognitive
resources it releases.