**Math:** the systematic treatment of magnitude, relationships between figures and forms, and relations between quantities expressed symbolically.

Also, mathematical procedures, operations, or properties.

## Dictionary : Letter X

**X**

The letter “x” is often used in algebra to mean a value that is not yet known.

It is called a “variable” or sometimes an “unknown”.

**X Axis**

The line on a graph that runs horizontally (left-right) through zero.

It is used as a reference line so you can measure from it.

**X Coordinate**

The horizontal value in a pair of coordinates: how far along the point is.