If you want to modify the display of a single data cell or a group of unassociated data cells this is done by selecting the individual cells, right clicking, and using Format (Data Cell).
Individual Data cells cannot be hidden but you can replace their contents with Custom Text. Of course, the number of decimal places, fonts, alignment, and indentation can be changed using the options in the Format (Data Cell) dialog above.
You can hide or otherwise modify entire rows or columns of numbers. Select the rows or columns to be modified (multiple selection is done using Shift and/or Ctrl keys), right click and use Format (Stub) for rows or Format (Column Head) for columns.
The settings that have an effect on the numbers in the rows or columns associated with the stub or column head are in the "Associated Cells" section. These check boxes allow you to extend the format of the stub/column head into all the cells in the corresponding row/column. Of course, the number of decimal places affects only the data cells themselves and not the column head or stub.
See Also: Formatting Row, Column, or Cell Data, Hide or Show a Row or Column