Five [laws require the addition of] a fifth: [If] one eats terumah, terumah of the tithe, terumah of the tithe of demai, challah, or bikkurim, he must add a fifth; [if] one redeems his reva’i plantings or his second tithe, he must add a fifth; [if] one re-deems his consecrated objects, he must add a fifth: [if] one derives benefit the worth of a perutah from consecrated articles, he must add a fifth; and [if] one robs another of the worth of a perutah and swears to him, he must add a fifth.