Background: In the last decades, children's understanding of mathematical principles has become an important research topic. Different from the commutativity and inversion principles, only few studies have focused on children's understanding of the addition/subtraction complement principle (if a - b = c, then c + b = a), mainly relying on verbal…

This paper introduces a revised model for the development of basic computation skills. The model draws on four key phases, which have proven to be important for the development of calculation strategies and stresses the use of gestures and the verbalisation of concrete and mental images. This seems to be of crucial importance for children with…

Examined whether indexes of verbal imprecision could be quantified and used to predict changes in fifth graders' problem-solving performance. Found that four types of verbal imprecision predicted improved performance: false starts and self-repairs, deletions, long pauses, and metacognitive comments. Results suggested that adopting a new approach…

Discussed is use of pictorial aids to develop word problem skills for addition and subtraction of handicapped children. (MC)