Top Rated Apps for Common Core Standards:

LearnZillion

LearnZillion:
The LearnZillion app offers a free and growing Math and English Language curriculum that has been developed by expert teachers directly from the Common Core State Standards. Thousands of exceptional lessons for teaching or learning the new standards. You don’t have to start from scratch anymore.

Google Play Store details:
Ratings – 4.1
Installs – 1,000 – 5,000
Developers – LearnZillion