Our communication fits into a wider study dealing with the activity of the
learner and of the teacher during the solving of numeric problems at primary school.
This article focuses on the first stage of our research, during which we examined the
place given explicitly by the teacher to the conversion of representation registers,
within the framework of solving numeric problems at primary school. It describes
and analyses a practice of education which allows us to examine on the one hand
how a teacher delivers, this conversion of registers to the learner in an explicit way
and then how learners take into account this devolution in order to practice useful
conversions during the problem-solving activity.