Percent Change

This sketch allows students to gain experience at estimating percent change. Either numerically estimating a visual change, or visually estimating a numerical change. It was inspired by Dan Pearcy's sketch comparing percent increase and decrease. blogpost: http://danpearcymaths.wordpress.com/2013/10/08/percentage-increase-and-decrease-applet-any-improvements/ sketch: http://www.geogebratube.org/material/show/id/52067 I'd be very interested in your feedback about how to make this one more engaging or meaningful. Or to make it a game!
More GeoGebra at mathhombre.blogspot.org