I am currently using level B and C with my first and second graders.
I do remember level B being difficult right in the middle. But I re-read the lesson alone, and stepped back for a a day or two. It seem to help both of us. I really didn't give up even though it was so frustrating. Now in Level C with my other one things make so much sense. I am very happy with Right Start it's giving them a good math foundation and understanding. The yahoo group offers great help and its a great place to ask questions and find encouragement from Right Start users.
HTH, Liz