A free program for Android, by Learning Loops.
Maths Loops + is an educational game that will help you improve your math skills. It includes three different exercises:
Addition and subtraction with and without a carrying or borrowing.
Each exercise has two pages. The first page is a preview, where you can see the result of your exercise and identify the mistakes you made. The second page is the correction page. Here, you have to correct the mistakes you made and the mistakes are highlighted as you correct them.
Each exercise has three difficulty levels. The first level is easy, the second level is medium, and the third level is hard.
The exercises are designed to be fun and easy to play.