Pre-Algebra

PS 18, #1, 5-12, 14, 16, 17

rev 3A

PS 16, #1, 2, 4, 7-16, 22, 25, 26

PS 15, #5-16, 25-27

PS 14, #6-15, 24-26

ps 12, #3-9, 11, 13, 15, 19, 20, 23, 24