I'm not real familiar with the application of this math series, but have read mixed reviews about it online from parents to educators who have evaluated the program. It is my understanding this program does not teach basic skills and fundamentals needed to succeed in higher math courses, such as pre-algebra, algebra, etc. I am concerned about using this program as a teacher of fourth-sixth grade students because it encourages the use of calculators and manipulatives. I still feel that teaching through memorization and steps is the best method to teaching the more difficult concepts so that students are able to compute on their own, without a calculator. How do some of you feel about this program with teaching older students math? How many of you have positive or negative experiences with this math series? Thank you for your feedback.