The currency in Cairo is the Egyptian pound ("gunaih" in Arabic). Egyptian notes are divided into piastres and pounds. Piastre notes come in 5, 10, 25, and 50; Piastre notes come in 1, 5, 10, 20, 50, and 100. Silver coins are hardly used (they come in 5, 10, 20, and 25), so don't expect to handle these much. If you are expecting change of a silver coin, you probably will receive gum or candy as compensation and not the coin.