Resumen de How primary school students perform multiplicative structure problems with natural and rational numbers
Cristina Zorrilla Victoria, Ceneida Fernández Verdú 
, María Consuelo Cañadas Santiago , Pere Ivars Santacreu
This paper is part of a larger study focuses on a teaching experiment (pre-test, instruction, post-test) that aims to analyse primary school students' features on the transition from natural to rational numbers when solving multiplicative structure problems. Here, we analysed 61 6th graders responses to nine multiplicative structure problems with natural numbers and fractions (pre-test). We analysed students’ performance and strategies. Results showed differences in students' performance considering the numerical set, indicating difficulties in identifying the problem structure's invariance. The most used strategy was the algorithm in both correct and incorrect answers. Results suggest that specific instruction is needed to help students focus on the problem structure invariance when the numerical set changes.
