This workbook is the NEW VERSION ISBN: 9780941995399. Contents of New version are IDENTICAL to old version; only difference is in the binding. New version is Perfect-Bound for strength and durability (Glued in pages), not comb-bound like old version. This 90 page Workbook is designed to assist in teaching the Addition and Subtraction lessons in the textbook: How To Tutor, Sam Blumenfeld's great book that tells you how to teach the three R's. Practice...