This app actually teaches basic multiplication and division as opposed to just testing existing knowledge. It is designed based on my experiences teaching my daugther school mathematics.
The app uses a step-wise approach, first using a visualization to help understanding, then practicing the tasks in an intelligent way. It also teaches the numbers 1 to 10 in a particular order which is easier to learn.
There are many motivating features and the app uses gamification elements such as a medal board to keep interest up.
The app is completely self-explanatory, even to a child, and it teaches and motivates at the same time. I have used and tested it with my own daughter with great success.