Can the Bible be the word of God, when there are multiple versions of it?

I recently found out on quora that the Catholic Bible has 73 books; the Orthodox Bible contains 76 or 77 books; the Protestant 66; and the Ethiopian Orthodox Tewahedo (Amharic) has 81 books. With these differences, how can all these Bibles be the word of God; if there is no standard version? How does one convince a non-Christian that the Bible is the infallible word of God, when there is no agreement as to what books make up the Bible?