Numbers 1:44

“These [are] those that were numbered, etc.] 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.”

“The enrollment, being taken principally for military purposes (compare Numbers 1:3, Numbers 1:20), would naturally be arranged by hundreds, fifties, etc. (cf. 2Ki 1:9, 2 Kings 1:11, 2 Kings 1:13). In eleven tribes the number enrolled consists of complete hundreds. The difference, in this respect, observable in the case of the tribe of Gad here Numbers 1:25, and of the tribe of Reuben at the later census Numbers 26:7, is probably to be accounted for by the pastoral, and consequently nomadic, habits of these tribes, which rendered it difficult to bring all their members together at once for a census. Judah already takes precedence of his brethren in point of numbers (compare Genesis 49:8…”

“Num 1:2-16, Num 26:64 Numbers 1:46”