We confronted 151, 5th and 6th elementary grade pupils with a quantitative problem in a mathematics or religion class, to examine the influence of the context on pupils' understanding and solution of such problems inside and outside the mathematics class. Pupils were first asked to solve a problem about fair sharing either during a mathematics or a religion class. Afterwards, they had to evaluate several (fictional) answers for this problem. We compared the responses and evaluations from both groups and found that (1) in the mathematics class pupils preferred precise numerical answers, while in the religion class pupils had a preference for a verbal description of the solution; (2) pupils in the mathematics class preferred answers motivated by calculations, while in the religion class, pupils favoured non-numerical arguments; (3) the concept ''fairness'' was interpreted and used differently in both conditions, leading to different preferential situational and mathematical models and solutions. (Contains 5 tables.)