Abstract
An atypical word problem of the type "What number makes sense?" is a tool that a teacher can use to develop students' argumentation skills and connect language and mathematics literacy. The task is to complete the numbers into the text so that they make sense in terms of approaches of mathematics, linguistic and real-life context.
Pairs of sixth and fifth graders solved a series of three problems and commented on their solutions. Their comments and non-verbal communication illustrate what phenomena initiate the heuristic strategies that the pupils used in the solution, and what errors they made in the solution.