Numbers won’t open in ipad

The obvious (or perhaps not so obvious) thing to check is whether or not the file with which you are having difficulty is actually a Numbers file - and not something else…

Using your Files App, navigate to the file that you need to check. When you locate the file, touch-and-hold (i.e., a long touch) to expose an Action Menu. From the menu select Get info - this will open a properties page. Check that the file is a Numbers Spreadsheet.

For example:

If the file is identified as a Numbers Spreadsheet, but will not open when other files of this type can be opened successfully, then the file is corrupt - and cannot be opened.

If the file is not a Numbers Spreadsheet - or a filetype that cannot be directly imported - then you’ll not be able to directly open the file in the Numbers App.