The idea that position could be identified by ordered pairs of numbers on a set of crossed number lines is thought to have been 'discovered' by Rene Descartes in the early 1600's. Apparently he thought of it while watching a fly crawl around on ceiling tiles.

He identified the location of a point on a flat suface using two numbers, written as an ordered pair (x , y) where the x number determined right/left position, and the y number up/down position. For example, the point (3 , -5) would be located three to the right and 5 down.

Let's see how good you are at identifying points located this way. Below is a Cartesian coordinate system with some points located on it. Identify each of the points, and then check your answers below.

Enter the points with brackets and a comma between: for example,   (-5 , 3)

Point A:    Point D:    Point G:
Point B:    Point E:    Point H:
Point C:    Point F:     Point I :
Point J:    The center point:

Scroll down for the answers. Don't peek until you're done!


A: (2, 4)     B: (4, 1)     C: (0, 2)     D: (-5, 3)     E: (-3, 0)     F: (-2, -4)     G: (-6, -1)     H: (0, -2)     I: (4, -2)     J: (6, 0)     centre (0, 0)