The document introduces the coordinate plane as a tool for working with equations in two variables. It explains how to create a coordinate plane by drawing perpendicular x and y axes that intersect at the origin, and using the axes to locate points on the plane using ordered pairs of numbers (x,y) as coordinates. It describes how to plot points by starting at the origin and counting along the x-axis and y-axis according to the x and y coordinates of the point. Finally, it divides the coordinate plane into four quadrants.