Coordinate Grid & Graphing

A coordinate grid is a flat map made of evenly spaced horizontal and vertical lines. Every point on the grid has its own address called an ordered pair, written (x, y). Coordinate grids are used in maps, graphs, video games, and science to show exactly where something is.

Parts of the Grid

• The x-axis is the horizontal number line that runs left to right.
• The y-axis is the vertical number line that runs up and down.
• The origin is the point (0, 0) where the two axes meet; on a full grid the axes make four quadrants, and this lesson uses Quadrant I, where x and y are both positive.
• Each square on the grid is one unit wide and one unit tall.

Ordered Pairs (x, y)

• Always write the x-coordinate first and the y-coordinate second.
• The x-coordinate tells you how far to move ACROSS from the origin.
• The y-coordinate tells you how far to move UP from there.
• The order matters: (3, 5) and (5, 3) are different points.

Plotting a Point

• Start at the origin (0, 0).
• Slide along the x-axis to the x-coordinate (move right).
• From there, slide up to the y-coordinate.
• Mark the point with a clear dot and label it with its ordered pair.

Reading a Plotted Point

• Drop straight down from the point to the x-axis to read the x-coordinate.
• Slide straight left from the point to the y-axis to read the y-coordinate.
• Write them as (x, y) with a comma between.