John Gill Commentary Numbers 1:44

"These are they that were numbered, whom Moses and Aaron numbered, and the princes of Israel, being twelve men: they were each one for his fathers` house." — Numbers 1:44 (ASV)

These [are] those that were numbered
Or, as the Targum of Jonathan, these are the sums of the numbers; namely, those before given of the several respective tribes:

which Moses and Aaron numbered, and the princes of Israel, [being]
twelve men ;
for though the tribe of Levi was not numbered, yet Joseph having a double portion, his two sons are reckoned as distinct tribes; so that one out of each tribe made up the number twelve:

each one for the house of his fathers ;
for the tribe he belonged to, with which it might reasonably be supposed he was best acquainted, and could more readily take the number of them.