Midrasch zu Schemot 9:10

(Exod. 30:13:) A HALF SHEKEL. R. Judah and R. Nehemiah differ. R. Judah says: Because (in the matter of the calf) they sinned in the middle of the day, they would give the half shekel. But R. Nehemiah said: Because they sinned for six hours in the day, they would give the half shekel,²²ySheq. 2:4 or 3 (46d); see Tanh., Exod. 9:10. See also below, Exod. 9:13. since it consists of six grammata.²³The Greek word (gramma in the singular) denotes a small weight of 1/24 ounce. R. Judah bar Nehemiah said in the name of R. Johanan ben Zakkay: Because Israel transgressed (rt.: 'BR) the Ten Commandments, they would give ten gerahs.²⁴Cf. Exod. 30:13 = Numb. 3:47: THE SHEKEL IS TWENTY GERAHS. Similarly Lev. 27:25; Numb. 18:16; Ezek. 45:12. R. Berekhyah said in the name of Resh Laqish: You sold Rachel's first-born for twenty <pieces of> silver (according to Gen. 37:28); therefore, in the case of every first-born that you shall have, his redemption shall be five shekels of silver, as stated (in Numb. 3:47): YOU SHALL TAKE FIVE <SHEKELS> EACH.