DocumentationMathematicaFront EndMenu CommandsCell MenuCell Grouping
Open/Close Group toggles a cell group between open and closed. Closing a group collapses all cells in the group so that only the head cell is visible.
You can also open or close a group of cells by double-clicking the bracket that spans a group of cells.
Keyboard shortcuts: ' (Windows); ' (Macintosh); ' (X).