This paper presents some results of an investigation on the number sense of a group of pre-service secondary teachers from Spain. The objective of this research was to analyze students' use of strategies associated to number sense and compare them with those obtained in a previous study with pre-service primary teachers in Taiwan, (Yang, Reys…

Comparative studies in content and language integrated learning (CLIL) often show CLIL students to be at something of an advantage over their non-CLIL peers. However, such studies are often difficult to interpret given problems of cross-group comparability (different schooling systems, different number of instructional hours, bias attributable to…

This paper provides evidence on the sources of differences in inequality in educational scores and their evolution over time in four European countries. Using Programme for International Student Assessment data from the 2000 and the 2006 waves, the paper shows that inequality decreased in Germany and Spain (two "decentralised" schooling…

The study of errors made in subtraction is a research subject approached from different theoretical premises that affect different components of the algorithmic process as triggers of their generation. In the following research an attempt has been made to investigate the typology and nature of errors which occur in subtractions and their evolution…