We have an extensive Preschool Prep library, including videos, apps, and coloring books. I use them to supplement our homeschool curriculum. This app is alright if your child has gone through all the Fact Families already. What I wish it allowed for was selecting the particular range of Math Facts so the child can just drill what they are learning or have learned.
For example, my child is up to the Subtraction 7 facts in her math lessons. I can’t customize the app to show only those flash cards. It has 18-10, 10-6, etc in the mix that she hasn’t learned yet. So, it’s not particularly useful in that respect.