My son absolutely loves this. He finished the first book quickly and when we sit down for school he always grabs this book first. I am getting a set to start my 4yo daughter on them now because she is so interested in what he is doing. I have the teacher's guide but I don't use it often at all.
I use this for my 5 y/o and she loves it. We tried Hooked on pre-k last year and she was bored This year for kindergarten we tried get set for the Code and she has learned so much from it! We are buying the next 3 books in this series to finish up this year and begin next.
My 4 y/o loves the books. This is her second in the series and I have to make her stop each day or she would complete the entire thing. The instructions are simple and easy for children to complete. We look forward to Book C and entering Explode series.