Self-paced flexbook (textbook)
Website: http://www.ck12.org/
Free Android Phone app: https://play.google.com/store/apps/details?id=org.ck12.app.practice
Free Android Tablet app: https://play.google.com/store/apps/details?id=org.ck12.app.practice
Google Chrome app: https://chrome.google.com/webstore/detail/ck-12/ilmbnmigihncgeckjgmkehcgkdeohkhl
Free iPad app: https://itunes.apple.com/us/app/ck-12-free-fun-way-to-learn/id909343639?mt=8&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/ck-12-free-fun-way-to-learn/id909343639?mt=8&at=10l6SU
Website: https://noredink.com/
Website: http://www.kidrex.org/
Google Apps for Education app: https://www.google.com/enterprise/marketplace/viewListing?productListingId=7980+8894534844862832232
Website: http://www.dreambox.com/
Website: http://www.nationalgeographic.com/
Website: http://www.mobymax.com/
Paid iPhone app: https://itunes.apple.com/us/app/letterreflex-overcoming-letter/id485920074?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/letterreflex-overcoming-letter/id485920074?mt=8&uo=4&at=10l6SU