Exodus 30:13

30:13 Everyone who crosses over to those who are numbered is to pay this: a half shekel according to the shekel of the sanctuary (a shekel weighs twenty gerahs). The half shekel is to be an offering to the Lord.

Leviticus 27:3

27:3 the conversion value of the male from twenty years old up to sixty years old is fifty shekels by the standard of the sanctuary shekel.

Leviticus 27:25

27:25 Every conversion value must be calculated by the standard of the sanctuary shekel; twenty gerahs to the shekel.