*** “English Grammar – Preposition” was reviewed and deemed educationally valuable by an independent group of educators in Google Play for Education.

*** Google Play for Education is a destination where schools can find great, teacher-approved, educational apps and videos on Play Store. All apps on Google Play for Education are evaluated by a third-party educator network to ensure that they align with Common Core State Standards in the United States.
http://www.google.com/edu/tablets/#play-intro