Numbers 4:36

And those that were numbered of them by their families were two thousand seven hundred and fifty.

Cross-reference

Numbers 4:44 lists the Merarite count (3,200) for the same age range, paralleling this Kohathite count in the same census.

Numbers 3:28 records 8,600 Kohathite males of all ages; the 2,750 here are those aged 30-50, a subset of that total.