Ninety-nine | English | German | isiXhosa
If you take a two-digit number and subtract its reverse, and then take the answer and add its reverse, then the result is always 99 e.g. 42-24=18, 18+81=99.
VISUALmaths
VITALmaths
The VITALmaths and VITALmathsLIC site consists of a databank of short and funky video clips that
specifically interrogate the conceptual aspects of a mathematical idea, process or concept. Some of the video
clips contain strategic dialogues to encourage appropriate mathematical talk and conversation.
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SANDBOXmaths
SANDBOXmaths is a collection of more experimental video clips done by students in their mathematics
teacher-training classes and researchers wishing to use specific video clips in their teaching and research.
APPLETmaths
The APPLETmaths site consists of a selection of GeoGebra applets that were developed by students and
researchers for their research projects.
