LibreOffice 7.0 Mintppc32 on iBook G4
With LibreOffice Writer and Calc you can create and save files, but attempting to open these files will cause a crash out from the application. Maybe an older version is needed on these older computers?
For a writer program I can recommend Abiword, which is lighter. If you want, I can try to build an older version of Libreoffice Writer and / or Calc.
gnumeric appears to work fine for spreadsheets.
@arend I installed Gnumeric, haven't had time to check it out, but the documentation looked impressive. Thanks for the suggestion.