Hi Garry, Thank you for this excellent example of how an instructor can be successful by developing coping strategies to overcome weak points in their abilities. You have done in a positive way that serves as a teaching tool for your students. The slide rule is great I was trained on one when I was in college. Brings back many memories of struggling to master the concept of how to use it. Haven't used one for years but sure I could because of the tremendous professor I had that made learning to use it come alive. I wish you continued success in your teaching. I know your students will benefit from your direction, concern and experience. Gary