Hiding worksheets which are not required at present

There are no contains called a "worksheet" in Numbers. I think you mean a "sheet". However, just make certain ewe are using a common set of terms...

with regard to Numbers...

• a File (stored on a media device) contains a document
• a Document contains one of more sheets. The sheet names across the top of the documents window and are often named "Sheet 1" etc. You can rename a sheet by double clicking the name
• a Sheet contains a canvas on which you may place:
  • one, or more, Tables
  • graphics
  • text
  • shapes

OK. so you cannot hide a sheet. If there is more than one sheet, you can drag the sheet names around to change the order. Put the one(s) you use the most on the left and leave the others on the right

Welcome back Wayne!

Your wisdom has been much missed.

Regards,

Ian.