DocumentationMathematicaThe Mathematica BookA Practical Introduction to MathematicaInput and Output in Notebooks
1.10.14 Automatic Numbering
Two ways to set up automatic numbering in a Mathematica notebook.
The input for each cell here is exactly the same, but the cells contain an element that displays as a progressively larger number as one goes through the notebook.
These cells are in NumberedEquation style.