This research study, carried out in South Africa and the United States of America, investigated issues that may hamper prospective primary school teachers from writing acceptable problem posing scenarios involving the addition of fractions. Pre-service teachers (n=44) were asked to compose real life problems involving the addition of two fractions where the sum is greater than one. The data generated suggest that issues that hamper the writing of acceptable problem scenarios are an inability to recognise that uniform units must be used, i.e. that for units to be comparable they must be the same size and shape, that standard/formal units of measurement must be used rather than informal units, and that different units of measurement cannot be used to represent the same fractional part. Another issue is the apparent inability of some students to recognise that the sum of given fractions can be greater than one whole. Finally, the use of colloquial language and local context were considered in terms of posing appropriate word problems involving fractions.