This is Mobile Version -> Standard Version: http://www.geogebratube.org/m2689
Algorithm credit: Harry Marshall
Original: http://teachers.henrico.k12.va.us/math/GeoGebraPages08/Fraction_Simplify.html
Metadata on teacher tab at: http://geogebramath.org/lms/nav/activity.jsp?sid=__shared&cid=emready@k_7_number_sense&lid=2
