Friday, 14 November 2014

Geometer's Sketchpad - Percent Guesser

When using the Geometer's Sketchpad it is often better to "start from sketch, not from scratch". That is, give students a premade sketch rather having them build something from nothing (as many textbooks would have you do). We think this is a really simple and fun activity that helps students get a feel for how big a percent of a whole is. In the sketch the whole is shown and a percent is given and the user has to drag the green dot to where they think that percent is.


  • Gr7NS - solve problems that involve determining whole number percents, using a variety of tools
  • Gr8NS - as review  
  • MPM1D - as review
  • MFM1P - as review
  • All that is needed is the electronic download
  • Note that this really works well on an iPad using the Sketchpad Explorer App (which is free)
  • You can also use this on any web based computer (or Chromebook) with this Web sketch
Watch the video below to see how to use the sketch.


Did you use this activity? Do you have a way to make it better? If so tell us in the comment section. Thanks