'Twenty' in the Bible

And thy valuation shall be of the male from twenty years old even unto sixty years old: thy valuation shall be fifty shekels of silver, after the shekel of the sanctuary;

And if it be from five years old even unto twenty years old, thy valuation of the male shall be twenty shekels, and for the female ten shekels.

And all thy valuation shall be according to the shekel of the sanctuary: twenty gerahs shall be the shekel.