Sabrina Goldberg is the 7th grade Math Teacher at The School at Columbia University. She has a classic project she initiates every year with her students:
A rectangular box is made by folding an cutting an 8″x10″ shet of paper. The Flap EF equals the height AB of the box.
EF + ED + DC + BC + AB = 10″
DC + CR + RS = 8″
The 8″x10″ sheet of paper costs $4.00.
It cost $0.02 per inch to cut the paper.
You can sell scrap paper at $0.06 per square inch.
It costs $0.20 per inch to tape up the corners.
You can sell the finished box for $0.30 per cubic inch.
Make such a box with a depth of 1.5 inches.
If you make cut AB = 1.5 inches, find:
volume of the box
cost of the cuts
value of the scraps
selling price of the box
surface area of the box outside, not including the flap
Build expressions above using AB = x inches
Daniel Scher is a principal investigator for The Dynamic Number Project. He works to create the iPad-compatible constructions for the Sketchpad Explorer app. Sketchpad Explorer is the iPad companion to Geometer’s Sketchpad software program – both are published by Key Curriculum Press (@keypress on Twitter).
Daniel will be coming to The School at Columbia University to help me help the 5th grade teachers integrate Sketchpad Explorer into their math curriculum. He’s psyched to watch/evalutate how kids learn with the app versus the software versus without either, and I’m excited to get a full grade of teachers to use a tool that I consider to be an industry standard for math educators. I love Geometer’s Sketchpad, and I recently gushed about Sketchpad Explorer on Scholastic’s Best in Tech Today.
Upon opening the Sketchpad Explorer app, there is an animated proof of the Pythagorian Theorem.
On the bottom right corner is a book icon. This takes you to many options, one of which is to visit the Sketch Exchange community site. From here, you can click Sketch Exchange sketches tagged with ipad, and then you can choose dynamic numberin the tag cloud. These sketches open up with the full Geometer’s Sketchpad software program as well.
There are four pages of sketches to choose from. I initially chose Balance Scale: Solving for Unknowns Part 1. When you choose a sketch, further down the page you’ll find links to download activity notes, worksheets, and the actual sketch with the .gsp suffix. I was super excited to note the CreativeCommons license (!) of Attribution Non-Commercial No Derivativeswhich translates to: Give me credit, don’t make money off it, and don’t alter it. I love Creative Commons almost as much as Geometer’s Sketchpad. 🙂
I had a bit of fun playing with this screen trying to figure out the value of the star and other shapes using the fulcrum, and yes, I think I’m smarter than a 5th grader.
Download the Sketchpad Explorer app here: http://itunes.apple.com/us/app/sketchpad-explorer/id452811793?mt=8