Why to teach geometry? (English)

Mammana, C., ICMI study - Perspectives on the teaching of geometry for the 21st century. ,. 53-58 (1995).

Teaching geometry is more complex and often less successful than teaching numbers and calculation. Therefore why to teach geometry to all students? This question commands another one: how to teach geometry? In order to put forward some ideas to this basic question, we must take in account the underlying cognitive complexity of geometry activity. (orig.)