Old Testament readings use the Septuagint , the Scripture the apostles quoted. Masoretic numbering shown for reference.Learn why
LXX

Numbers 11:16

And the Lord said to Moses, Gather me seventy men from the elders of Israel, whom thou thyself knowest that they are the elders of the people, and their scribes; and thou shalt bring them to the tabernacle of witness, and they shall stand there with thee.

Read in other translations