Numbers 3:22

Those that were numbered of them, according to the number of all the males, from a month old and upward, even those that were numbered of them were seven thousand and five hundred.

Cross-reference

Numbers 3:15 commands the census of all Levite males – the instruction that produces this count.

Numbers 3:39 gives the total Levite count (22,000) – of which the 7,500 Gershonites here are part.

Numbers 4:38-40 counts Gershonites aged 30-50 for service – a subset of the total males counted here.

Numbers 4:44 counts Merarites for service – a parallel census of a different Levite clan.

Joshua 21:6 assigns land to the Gershonites – the tribe whose census number is given here.