A list of digital calculators available
Paid iPad app: http://itunes.apple.com/us/app/graphing-calculator-hd/id374274107?mt=8&uo=4&at=10l6SU
Paid iPad app: http://itunes.apple.com/us/app/pi-cubed/id311433261?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/pi-cubed/id311433261?mt=8&uo=4&at=10l6SU
Paid iPhone app: http://itunes.apple.com/us/app/pi-cubed/id311433261?mt=8&uo=4&at=10l6SU
Google Chrome app: https://chrome.google.com/webstore/detail/bhdheahnajobgndecdbggfmcojekgdko
Website: https://www.desmos.com/
Edmodo app: http://www.edmodo.com/publisher?uid=3382251
Free iPad app: https://itunes.apple.com/us/app/graphing-calculator-by-desmos/id653517540?mt=8&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/graphing-calculator-by-desmos/id653517540?mt=8&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.desmos.calculator
Free Android Tablet app: https://play.google.com/store/apps/details?id=com.desmos.calculator
Free Android Phone app: https://play.google.com/store/apps/details?id=com.visionobjects.calculator
Free iPhone app: https://itunes.apple.com/en/app/myscript-calculator/id578979413?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/en/app/myscript-calculator/id578979413?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/app/ti-nspire/id590823242?mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=net.supware.tipro
Free iPad app: https://itunes.apple.com/us/app/free-graphing-calculator/id378009553?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/free-graphing-calculator/id378009553?mt=8&uo=4&at=10l6SU
Paid iPad app: https://itunes.apple.com/us/app/scientific-graphing-calculator/id369480853?mt=8&uo=4&at=10l6SU
Paid iPhone app: https://itunes.apple.com/us/app/scientific-graphing-calculator/id369480853?mt=8&uo=4&at=10l6SU