My son used it exclusively in 1st – 3rd grade. We completed all of the elementary books in those years. There’s lots to love about Fred. I can truly see how it taught my kids to think mathematically. The lessons are short, but how much math do you need when you’re 8 years old? 🙂 The one thing you absolutely MUST do with Fred is make sure the child understands what he’s doing and why. If they get a problem wrong, you need to go back and help them understand what went wrong. After finishing the elementary series, I did not think he was ready for Kidneys-Liver-Mineshaft or the Fractions & Decimal books, so we are doing Teaching Textbooks for a while. I think having both is good. TT gives them the practice and drill-type work that they need as they get into more complicated math. My son went directly from the last LOF elementary book to 6th grade TT. (He is about to turn 10) He is making 90’s on the lessons and 100 on the quizzes in TT, so I definitely think Fred did a good job of preparing him. We will definitely do the Fraction and Decimal books at some point, but probably after he has a couple of years of TT under his belt. My older kids have done the elementary series also, but not exclusively since they came out after they had already done a lot of math. I found that once we got to Algebra, though, Fred just wasn’t enough instruction and practice for them, so we use Jacob’s Algebra.
Here’s the thing about LOF. It’s a totally different way of learning math. There is no direct instruction. You kind of have to infer how to do things. Sometimes that takes a lot of effort. And sometimes, like with Algebra, I think you do need direct instruction. If you don’t have a kid who naturally wants to understand everything (I don’t), you have to make sure you are on top of things and check for understanding before moving on. For the elementary series at least, I think the parent definitely needs to be reading each and every lesson with the kid and making sure he’s learning what he needs to learn.