I tried the first book of Learn Math Fast last school year. It didn’t work out well for us. You are instructed to stay in each section until your child knows it well, then move on. That means we just copy the same worksheet and do it over and over and over again and feel like we are making no progress. We did not “learn math fast,” we just spent lots of time on the first few chapters of the book. By the end of the year, none of my children had made much progress at all. We are starting a different program this year.
That said, Learn Math Fast has many positive reviews so it works for some people! I think it would work well for a child who could quickly catch on to a concept and retain it without needing lots of repetition.
You use real pennies for learning addition and subtraction and there is a funny jingle to sing when learning to add two digit numbers to one digit numbers. If these things appeal and she’s good at picking up concepts without a lot of practice, this series might work for her.
But it is not at all a spiral program. Hope that helps!