add numbers document as a sheet

If your other document is all in one sheet you can Select All, Copy, then paste into a blank sheet in the other document. All the interrelated formulas should continue to work as they did, though some functions like INDIRECT might fail if the sheet name was in the formula and is different now. All interrelated tables and charts need to be on the same sheet so they can all be copy/pasted at the same time. Stand-alone tables and objects can be copy/pasted individually.

You can also do this:

In the document that you want to "add" to another document:

Hover over a sheet "tab", click the v to its right and select Copy Sheet.

In the document to which you want to add that sheet:

Hover over any sheet "tab", click the v to its right, and select Paste Sheet.

Repeat with other sheets as necessary.

SG