In this paper we report on the sustained research and development work at the AMSTEL Institute of the University of Amsterdam to improve mathematics and science education at primary and secondary school level, which has lead amongst other things to the development of the integrated computer working environment Coach 6. This environment consists of integrated tools for data collection (through measurement with sensors or collection of data on video clips and digital images), for control of processes and devices, for processing and analyzing data, for construction, simulation, animation, and validation of computer models, and for authoring of activities by teachers and students. It is meant to facilitate the students' construction of in-depth and integrated understanding of mathematics and science concepts and processes through inquiry. This is realized by offering students the opportunity to work directly with high-quality, real-time data by means of tools that resemble technologies used by "real" scientists. We review the R&D work at AMSTEL in the Dutch perspective on introducing learning technologies in school mathematics and science. We also present an illustrated review of the principled design and implementation of Coach 6. (Contains 6 figures.)