One of the main questions in this paper is: ‘Should knowledge be provided or generated in mathematics education?’ In trying to respond on this fundamental question it became clear that this dichotomy is not fruitful. Therefore we looked for a third way in which guided cooperative learning was a component in a new teaching and learning arrangement for students between the Ages of 10 and 16. Two such arrangements were designed, described, implemented and the learning results presented: the so called ‘AGO-model’ (Adaptive instruction and Guided co-operative learning) and the ‘GCC-Model’ (Guided Co-Construction). From our research in a series of design experiments we may conclude that both instructional approaches are feasible and effective in mathematics education. Both AGO and GCC were effective in a pretest-posttest control group design. Moreover, significant transfer-effects could be determined. There are reasons to believe in a happy marriage between guided cooperative learning and mathematics education. However co-operative learning is no cure for all. And cooperative learning should always be accompanied by other instructional strategies like whole class introductions and reflections which should be led by the teacher. The curriculum materials should be special designed for guided cooperative learning. Last but not least, mathematics should be taught in a meaningful, but mathematically honest way. Otherwise ‘mathematics for all’ may result in ‘no mathematics at all’. In mathematics education we need to create a knowledge-rich learning environment which is directed to the central concepts, procedures and structures of mathematics
