Working Title: Asking Questions and Making Conjectures
Dan Meyer, a former secondary math teacher in northern California, has fantastic ideas for math teachers. See Dan's blog and Dan's 2010 TED talk, for a sample of his work and ideas.
Let's discuss now one of Dan's "Three-Act Math Tasks." Dan Meyer's Pyramid of Pennies, Three-Act Math Task
Dynamic proof: sum of squares of first n natural numbers, by Irina Boyadzhiev
Now that you know (and/or remember) the formulas for (1) the sum of the first $n$ natural numbers and (2) the sum of the squares of the first $n$ natural numbers, you should practice using the formulas. Click on the following link to do this now: Practice Some Sums (with GeoGebra).
Load Pascal's Triangle GeoGebra worksheet