I did have Rebekah do Key to Fractions, Book #1: pages 1-4. And realized that she is retaining ABSOLUTELY NOTHING from Teaching Textbooks. She rarely got under a 90% for the lesson, but apparently there's just something about the program that she's not getting. I don't really know what to do.
I also introduced her to Fred. She's fallen in love! =) I found some books for multiplication and division (plus a few other concepts) that seem similar to Fred. I'm toying with the idea of having her do those 2 books before trying to move on.
Stanley F. Schmidt, author of Life of Fred, claims that the upper level books are complete. Cathy Duffy, on her review website, placed Life of Fred under "Math" not "Math Supplements." This leads me to believe that maybe they are! I know that there is a lot of controversy about this, but I've got 2-3 years to decide.