Leviticus 27:6
If a person is from one month to five years old, then your valuation for a male is to be five shekels of silver, and for a female your valuation is to be three shekels of silver.
Numbers 3:40-43
Later the LORD instructed Moses: "Number all the first-born males of Israel from a month old and above and list their names.
Numbers 18:14-16
Every devoted thing in Israel is yours, too.
Treasury of Scripture Knowledge
Summary
And if it be from a month old even unto five years old, then thy estimation shall be of the male five shekels of silver, and for the female thy estimation shall be three shekels of silver.
Bible References
From
Numbers 3:40
Later the LORD instructed Moses: "Number all the first-born males of Israel from a month old and above and list their names.
Numbers 18:14
Every devoted thing in Israel is yours, too.