Numbers spreadsheet abruptly closes down

Working on Numbers app from on iPad Pro(4th gen) wifi only:

Every time I attempt to add or make a change to any column or row on any form within my personal budget spreadsheet that I have been preparing all month with no issues now it immediately shuts down as in the entire app closes. When I go into a separate budget spreadsheet this does not occur. Can anyone assist with information to correct this problem? I don’t want to have to start from scratch to redevelop all the forms and input all the information in a new spreadsheet as I said I have worked on this all month. Thanks in advance.