Rasmus - Math, Ordered pairs (coordinates), Lesson 1

A cordinate system has 2 axes that form a 90° angle. The X axis is horizontal and the Y axis is vertical. The point where they meet is called the origin and has the coordinates (0,0).

To plot a point

for example ( -1, 1) in a coordinate system, you count from the origin (0, 0) . The first number in the pair (-1 in our example) indicates the number of spaces along the X axis (right + or left - ) and the second number ( 1 in our example ) indicates the spaces along the Y axis (up + or down - ).

The point A is (-1, 1)

First count one space to the left (-1) from (0,0), then one space up (+1) along the Y axis.

The following points can be plotted on the grid in the same way:

Point B has the coordinates: (-2,-2)

Point C has the coordinates: (2,2)

Point D has the coordinates: (5,-3)

PS. If you have played chess or Battleship, you probably know how to plot points like this.

Try Quiz 1 on Plotting coordinates. Remember to use your Checklist. If you score 80% or higher, go to the next topic.