FREE for a limited time – Flashcard Ninja, an educational app for practicing addition and subtraction with numbers 1 – 20. Kids embark on a journey to become a math ninja. They can record their own sounds to accompany the ninja’s karate moves – a feature that is sure to be a hit. As they answer mixed addition/subtraction questions posed by the ninja master, the “math ninjas” win trophies for their trophy room. A 10, 20, or 30 second timer can be set to allow more time for kids who need it. The timer can also be turned completely off. I wish there an option to customize a child’s practice – addition only, subtraction only, mixed facts up to 10, etc. It would also be nice if the app gathered data. That being said, I can see how this app might appeal to some kids who are otherwise reluctant to practice math. So, check it out while it’s free to see if it works for your children.