'Twenty' in the Bible

When thy valuation hath been of the male from a son of twenty years even unto a son of sixty years, then hath been thy valuation fifty shekels of silver by the shekel of the sanctuary.

and if from a son of five years even unto a son of twenty years -- then hath thy valuation been of the male twenty shekels, and for the female, ten shekels;

And all thy valuation is by the shekel of the sanctuary: twenty gerahs is the shekel.