Thematic Bible: Of the firstborn

And for the ransoms of the two hundred seventy-three of the firstborn of the sons of Israel, who are more than the Levites, thou shalt take five shekels apiece by the poll, after the shekel of the sanctuary shalt thou take them (the shekel is of twenty gerahs). And thou shalt give the money, of the ransoms of the odd number of them, unto Aaron and to his sons. read more.
And Moses took the ransom money of those that were over and above the ones that were redeemed by the Levites and received of the firstborn of the sons of Israel, in money, a thousand three hundred and sixty-five shekels, after the shekel of the sanctuary. And Moses gave the money of the ransoms unto Aaron and to his sons, according to the word of the LORD, as the LORD had commanded Moses.

Every thing that opens the womb in all flesh, which they shall offer unto the LORD, whether it is of men or animals, shall be thine; nevertheless the firstborn of man shalt thou surely ransom, and the firstborn of unclean animals shalt thou ransom. And from a month old shalt thou effect their ransom, a ransom according to thine estimation, for the price of five shekels, after the shekel of the sanctuary, which is twenty gerahs.