Abstract: One hundred and fifty-one Primary 5 (average age 10.7 years, sd = 0.65) pupils were asked to use the model method to answer five word problems. Pupils used the model method most successfully with an arithmetic-word problem. With the algebraic-word problems, the rate of success decreased from word problems where the nature of relationships was homogenous involving two additive relationships to that which involved non-homogenous relationships. Pupils errors were clustered around relational phrases such as ‘more than’, ‘less than’ and ‘n times as many’. Pupils who used the model method to solve word problems involving fractions showed that they had a superior command of how they visualised the problem. Their solutions showed that they oscillated between the symbolic representations of the problem and its visual analogue.