So Aaron had four sons that were consecrated, but two died before they could reproduce, so the legacy fell to the other two. Aaron’s descendants were put in charge of the tribe of Levi.
When Moses counted the Levites, he counted all the males from one month old up. By the three subtribes, or clans, there were 7,500 Gershonites, 8,600 Kohathites, and 6,200 Merarites. The Gershonites were put in charge of the Tabernacle tents, screens, etc. and were to camp to the west of the Tabernacle. The Kohathites were in charge of all the sanctuary furniture and were to camp on the south of the Tabernacle. The Merarites were in charge of the pillars, bases, etc. and were to camp to the north of the Tabernacle. Moses, Aaron and their families were to camp in the east, in front of the entrance to the Tabernacle.
Moses also counted all the firstborn male Hebrews, which came to 22,273 because God claimed them, and they had to be redeemed. God exchanged 22,000 Levites for most of them, and made the tribes pay five shekels a piece to Aaron for the other 273, for a total of 1365 shekels, so probably 34 1/8 pounds of silver.