truncate?

I don't have Excel 365 so I don't know if that version allows for a simpler formula or not, but here is an array-entered** formula that appears to work...

Formula:

=LEFT(A1,MAX(IF(ISNUMBER(-MID(A1,ROW(INDEX(A:A,1):INDEX(A:A,LEN(A1))),1)),ROW(INDEX(A:A,1):INDEX(A:A,LEN(A1))))))

**Commit this formula using CTRL+SHIFT+ENTER and not just Enter by itself

NOTE: I think you can normally-enter this formula in Excel 365 and it should still work.