The objective of this study was the design and development of mathematical technological activities. The guiding model in developing these activities was the Technology Acceptance Model (TAM). The two main issues to address, according to the model, are the “perceived ease of use” and the “perceived usefulness” of the software. The activities were used, refined and tested in a professional development
programme which consisted of five hands-on laboratory sessions, lasting 2 hours each, spaced over a 3-month period. The study found that the approach of letting teachers experience technology while engaged
in authentic mathematical tasks promotes the perceived usefulness of Geometer’s Sketchpad (GSP) by the teachers. At the end of the series of workshops, 91% of the teachers indicated in the summative evaluation that these workshops helped them to understand geometry better. This finding was supported by the 21.5% increase in the pre-test and post-test average score.