## Coordinates and points

Designed and produced by the Spanish CoI

The c-book unit ‘Coordinates and points’, targeting first-year secondary school students (12-13 years old), presents an introduction to the Cartesian coordinate system and the notion of ordered pairs. Two main objectives are defined:

(1) Concerning mathematical contents, the main idea is to give sense and help students understand points on a graph. Firstly, students are asked to reason qualitatively about the meaning of points plotted on a graph. Secondly, a quantitative notion is introduced in order to establish connections between points and get a preliminary notion of functions.
(2) Besides the main mathematical contents involved along the unit (data representation, negative coordinates, qualitative and quantitative interpretation of data table and graphs, etc.), the unit follows other learning goals concerning:
(a) build, use and analyse mathematical tools as an essential tool for communication and understanding of extra-mathematical situations;
(b) communicate, justify and validate the own students answers 