'Twenty' in the Bible

if your proper value is [for] a male from {twenty years of age} up to {sixty years of age}, then your proper value shall be fifty shekels [of] money according to the sanctuary's shekel.

And if from {five years of age} up to {twenty years of age}, then your proper value shall be twenty shekels [for] the male and ten shekels for the female.

And every proper value of yours shall be in the sanctuary's shekel--the shekel shall be twenty gerahs.