The following apps offer learning paths for kids and are available for the PC and as mobile apps.
ABCMouse.com allows your children to go through a online curriculum for ages 2 through 8 and offers an annual membership for $45.00.
Adventure Academy is for older kids from 8 – 13. You can get an annual membership for $45.00.
Starfall offers a variety of educational material for Pre-K/Kindergarten and Grade 1, Grade 2, and Grade 3. Home membership runs around $35/year. Starfall is accessible via a mobile app and also through a PC. The last time we used Starfall, the mobile app did not seem to have all the educational material that was available through the PC.
Curious World offers an app for kids age 3 to 7.