Midrash su Numeri 2:21

A census of Israel was taken on ten different occasions. The first occurred when they descended to Egypt, as is said: Thy fathers went down into Egypt with three score and ten persons (Deut. 10:29). Again, when they came out of Egypt, as it is said: And the children of Israel journeyed from Rameses to Succoth, about six hundred thousand men (Exod. 12:37). Once in the Book of Numbers (it was taken) with reference to the standards (Num. 2:21); once with regard to the spies (Num. 13);¹⁵There is no biblical evidence that a census was taken at the time of the spies.. in the days of Joshua when the land was divided (Josh. 18:10); twice in the time of Saul, as is said: And he numbered them with lambs in Telaim (I Sam. 14:4) and He numbered them with pebbles in Bezek (ibid. 11:8). What is indicated by the word Telaim? When they were prosperous, he counted them by means of their lambs (telayim), but when they were poor in deeds, he counted them with stones. What is bezek? It is a stone. He took a stone for each one of them and then totaled the stones. A census was taken in the days of David, as is said: Joab gave up the sum, the number of the people to the king (II Sam. 24:9); and again at the time of Ezra: The whole congregation together was forty and two thousand, three hundred and three score (Ezra. 2:14). In the time-to-come (a census will be taken), as is said: The flock shall again pass into the hands of Him that counteth them (Jer. 33:13), and in this instance: When thou takest the sum.