Introduction and outline

Abstract

Arithmetic, measurement and geometry are closely related. You could even say that measurement and geometry build a bridge between everyday reality on one side and mathematics on the other. Measurement is what we do when we quantify reality, i.e. when we allocate numbers in order to acquire a grip on reality. With these numbers, we can calculate and make comparisons and predictions. For example, we can determine how much of something we need, how long something will last, or how much something will cost. Geometry establishes the basis for understanding the spatial aspects of reality. We use geometric knowledge even without being aware of it, for instance when we plan a route, furnish a room or interpret a plan. In geometry education, we try to expand this informal knowledge.