## The Lesson

The x-coordinate is the first number in the pair of numbers used to describe Cartesian coordinates. For example, in the Cartesian coordinates**(2, 4)**, the x-coordinate is

**2**(the number on the left):

## What Does the X-Coordinate Mean?

The x-coordinate tells you how far**across**the horizontal x-axis a point is on a graph (measured from the origin). If a point has Cartesian coordinates

**(2, 4)**, the point would be

**2**units along the x-axis. The image below shows what we mean by a point being 2 units along the x-axis (measured from the origin):

**Note:**The x-axis is labelled with numbers (0, 1, 2, 3...) so you can measure how far across the point is.

## The X-Coordinate Can Be Positive...

If you go**right**along the x-axis (starting at the origin, where it crosses the y-axis), it is labelled with positive numbers (0, 1, 2, 3...). The x-coordinate of any point to the

**right**of the y-axis is

**positive**. Imagine a point had an x-coordinate of

**4**. It would be

**4**units to the

**right**of the y-axis:

## ...Or the X-Coordinate Can Be Negative

If you go**left**along the x-axis (starting at the origin, where it crosses the y-axis), it is labelled with negative numbers (0, −1, −2, −3...). The x-coordinate of any point to the

**left**of the y-axis is

**negative**. Imagine a point had an x-coordinate of

**−4**. It would be

**4**units to the

**left**of the y-axis:

## Which Axis Is Which?

The**x is a cross**- so the

**x-axis goes across**!

The y-axis must go up.