'One tenth' in the Bible

Abraham measured out one tenth of everything he had [taken in battle] and gave it to Melchizedek. (Now "Melchizedek" means, first of all, "King of Righteousness," and then [since he was] King of Salem, it also means "King of Peace").

At that very hour a severe earthquake occurred and one tenth of the city [See verse 8] was destroyed; and seven thousand persons were killed by the earthquake; and everyone else was terrified and gave honor to the God of heaven.