Numbers 3:15
“Number the Levites by their families and clans. You are to count every male a month old or more.”
Berean Standard Bible
Number the children of Levi after the house of their fathers, by their families: every male from a month old and upward shalt thou number them.
“Count the children of Levi by their fathers’ houses, by their families. You shall count every male from a month old and upward.”