I own VT module A but we haven't used it. WE've used Rightstart math A-E. Dr. Cotter hasn't had time to complete the RS series w/ RS algebraic Approach so she highly recommends VT A for a program which is in line w/ her philosophy of understanding the WHYs of math and not just the HOW which is why when I found it for a great price used I bought it. WE'll be starting it in the fall.