Tenoch E. Cedillo A.* (Mexico), tcedillo@ilce.edu.mx A number-based approach to introductory algebra: A study with 11-12 year olds using graphic calculators Research results obtained from using graphic calculators as mediating tools to help novice students express and justify generalisations are addressed. The study was carried out in different stages and school settings. In 1994-96 within a highly framed classroom environment, with 25 students and the researcher playing the role of the teacher. In 1997 the investigation continued, a real full-time teacher with a class of 40 students was in charge of the classroom and the researcher only observed and analysed the classroom work. Finally, in 1998, the research involved 18 middle schools throughout the country, around 100 teachers and 10000 students took part.