Leviticus 6:4-5

6:4 when it happens that he sins and he is found guilty, then he must return whatever he had stolen, or whatever he had extorted, or the thing that he had held in trust, or the lost thing that he had found, 6:5 or anything about which he swears falsely. He must restore it in full and add one fifth to it; he must give it to its owner when he is found guilty.

Leviticus 27:13

27:13 If, however, the person who made the vow redeems the animal, he must add one fifth to its conversion value.

Leviticus 27:15

27:15 If the one who consecrates it redeems his house, he must add to it one fifth of its conversion value in silver, and it will belong to him.

Leviticus 27:27

27:27 If, however, it is among the unclean animals, he may ransom it according to its conversion value and must add one fifth to it, but if it is not redeemed it must be sold according to its conversion value.

Leviticus 27:31

27:31 If a man redeems part of his tithe, however, he must add one fifth to it.

Numbers 5:7

5:7 then he must confess his sin that he has committed and must make full reparation, add one fifth to it, and give it to whomever he wronged.