Apps I found that would be useful in a fourth grade classroom.
Website: https://quizlet.com/
Edmodo app: http://www.edmodo.com/publisher?uid=507204
Free iPhone app: https://itunes.apple.com/us/app/quizlet/id546473125?mt=8&uo=4&at=10l6SU
Google Chrome app: https://chrome.google.com/webstore/detail/quizlet/bgofflgeghkhocbociocnckocbjmomjh
Free iPad app: https://itunes.apple.com/us/app/google-earth/id293622097?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/google-earth/id293622097?mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.google.earth
Free Mac program: http://www.google.com/earth/download/
Free Windows program: http://www.google.com/earth/download/
Google Chrome app: http://www.google.com/earth/explore/products/plugin.html
Mozilla Firefox extension: http://www.google.com/earth/explore/products/plugin.html
Apple Safari extension: http://www.google.com/earth/explore/products/plugin.html
Website: http://www.billnye.com/
Paid iPad app: http://itunes.apple.com/us/app/grammar-app/id377188655?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/grammar-app/id377188655?mt=8&uo=4&at=10l6SU
Website: http://www.discoveryeducation.com/
Free iPad app: https://itunes.apple.com/us/app/scholastic-storia/id491014756?mt=8&uo=4&at=10l6SU
Website: http://www.pbs.org/teachers
Free iPhone app: http://itunes.apple.com/us/app/miss-spells-class/id308754739?mt=8&uo=4&at=10l6SU
Website: http://www.learninggamesforkids.com/
Free iPad app: https://itunes.apple.com/us/app/bluster!/id416160693?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/storybuilder-for-ipad/id377631532?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/word-bingo/id406264088?mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/word-bingo/id406264088?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/geoboard-by-math-learning/id519896952?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/geoboard-by-math-learning/id519896952?mt=8&uo=4&at=10l6SU
Website: http://www.mathlearningcenter.org/web-apps/geoboard/
Google Chrome app: https://chrome.google.com/webstore/detail/geoboard-by-the-math-lear/gaakmmdiopnmcenkojohldanladpajak
Paid iPad app: http://itunes.apple.com/us/app/fractions-app/id387434956?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/fractions-app/id387434956?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/math-bingo/id371338715?mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/math-bingo/id371338715?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/number-pieces-basic-by-math/id611452042?mt=8&uo=4&at=10l6SU
Website: http://www.mathlearningcenter.org/web-apps/number-pieces/
Free iPad app: https://itunes.apple.com/app/math-champ-client/id516219415?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/app/math-champ-client/id516219415?mt=8&uo=4&at=10l6SU
Website: http://digitwhiz.com/
Free iPad app: http://itunes.apple.com/us/app/digitwhiz-math/id559968556?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/math-workbook/id467548534?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/math-workbook/id467548534?mt=8&uo=4&at=10l6SU
Website: http://www.mathatube.com/