NET
3 You and Aaron are to number all in Israel who can serve in the army, those who are twenty years old or older, by their divisions.
Darby
3 from twenty years and upward, all that go forth to military service in Israel: ye shall number them according to their hosts, thou and Aaron.
KJV
3 From twenty years old and upward, all that are able to go forth to war in Israel: thou and Aaron shall number them by their armies.