You write volume in cubic units by adding a superscript "3" to the unit of measurement.

Here's how it works:

* Start with the unit of measurement: For example, centimeters (cm), meters (m), inches (in), feet (ft), etc.

* Add the superscript "3": This indicates that the unit is cubed.

Examples:

* Cubic centimeters: cm³

* Cubic meters: m³

* Cubic inches: in³

* Cubic feet: ft³

Let me know if you have any other questions!