Fractions Decimals Percentages

This app is great for the intended age group (i.e. 6-8 years old). However, I was looking for an app that I was hoping I could use to help an adult relative who is trying to learn fractions and percentages because he never learned them as a child. I was drawn to this app because the description said "no silly games." So yes, there are no silly games in this app, but it nevertheless feels embarrassingly like a child's app (which is as stated in the description, so there is nothing misleading about that). However, my quest goes on for the right tool. SUGGESTION: I wish the developers would recycle their coding for this app to produce an app that would be visually more age appropriate for high school dropouts who are now struggling to learn math. Generally speaking these are people with self-esteem issues who may often feel like failures in life, so they don't need visual reminders in the learning app (e.g. the little girl in the lower right corner) that make them feel worse than they already do.