Thematic Bible: Of the firstborn

And for the redemption of the two hundred and seventy-three of the first-born of the sons of Israel, who are over and above [the number of] the Levites, thou shall take five shekels apiece by the poll. According to the shekel of the sanctuary thou shall take them (the shekel is twenty gerahs), and thou shall give the money, with which the odd number of them is redeemed, to Aaron and to his sons. read more.
And Moses took the redemption-money from those who were over and above those who were redeemed by the Levites. He took the money from the first-born of the sons of Israel, a thousand three hundred and sixty-five [shekels], according to the shekel of the sanctuary. And Moses gave the redemption-money to Aaron and to his sons, according to the word of LORD, as LORD commanded Moses.

Everything that opens the womb, of all flesh which they offer to LORD, both of man and beast shall be thine. Nevertheless the first-born of man thou shall surely redeem, and the firstling of unclean beasts thou shall redeem. And those that are to be redeemed of them from a month old shall thou redeem, according to thine estimation, for the money of five shekels, according to the shekel of the sanctuary (the same is twenty gerahs).