'Twenty' in the Bible

If your valuation is of a male between twenty and sixty years of age, then your valuation shall be fifty shekels of silver, according to the shekel of the sanctuary.

If the person is between five years and twenty years of age, then your valuation for the male shall be twenty shekels and for the female ten shekels.

Every valuation of yours shall be in accordance with the sanctuary shekel; twenty gerahs shall make a shekel.