We may be able to find where we live on a map, but would we describe it to somebody else? What if they were on the other side of the world and had no idea where our town was? A number line helps with direction, but only left and right, or up and down. This is where a number plane can help us.

A number plane is like having a horizontal number line and a vertical number line! We can describe the position of any point or location using two values, called a pair of coordinates.

Features of a Number Plane

A number plane is made up of a horizontal and a vertical axis.

The horizontal axis, called the$x$x-axis, is like a number line you have seen previously that runs from left to right.

The vertical axis, called the $y$y-axis, is a number line that runs up and down.

The two lines meet at the origin, which has coordinates $\left(0,0\right)$(0,0).

Plotting and naming coordinates

A pair of coordinates describes a point's position away from the origin.

When we plot a pair of coordinates, we draw them on a number plane. For example, to plot the point $\left(2,5\right)$(2,5), we would start at the origin, move $2$2 spaces to the right and $5$5 spaces up.

To name coordinates, we write the horizontal value, then the vertical value that a point is away from the origin. Watch this video to learn more about plotting and naming points on the number plane.

Remember!

We write the horizontal $x$x-coordinate, then the vertical $y$y-coordinate $\left(x,y\right)$(x,y).

Just like the alphabet, $x$x comes before $y$y.

Now you can have a play with this applet to practise plotting some points.