Efforts to meet the needs of children's learning in arithmetic has led to an increased emphasis on the teaching of mental calculation strategies in England. This has included the adoption of didactical tools such as the empty number line (ENL) that was developed as part of the realistic mathematics movement in the Netherlands. It has been claimed…

Analyzed construction of approximative expressions with two numerals in Dutch. Found that choice of number words was not arbitrary and that various kinds of factors are involved. Results suggest that analogue magnitude code is used in estimating and comparing, and human cognition seems to be able to perform simple calculations with quantities,…