Numbers 2:32-34

These are the men of the Israelites [twenty years old and upward] as numbered by their fathers’ households. The total of the numbered men of the camps by their armies, 603,550. But the Levites were not numbered with the [other] Israelites, just as the LORD had commanded Moses. Thus the Israelites did [as ordered]; according to everything the LORD had commanded Moses, so they camped by their standards, and so they moved out, everyone with his family (clan), according to his fathers’ household.