The coordinate plane has two perpendicular lines: the x-axis (horizontal) and y-axis (vertical). They cross at the origin (0, 0).
Every point is written as (x, y). The x value tells you how far left or right. The y value tells you how far up or down. For example, (3, 2) means 3 units right and 2 units up from the origin.
This system lets you describe any position with two numbers. Grid problems, map applications, and geometry calculations all use coordinates.