The "Digital Abacus" widget allows students who does not have access to a pen and paper to do quick calculations
Widget Learning Design Template,
Widget StoryboardLearning Design
Digital abacus that allows students to move the virtual balls of the abacus to calculate maths problems. The abacus could be semi transparent and should be easily resized.
Storyboard

Screenshots
How it works
Pretty simple, just click the balls to move them arround.
The "Reset" button generate a new abacus,
The +/- buttons allow you to add and remove row from the abacus.
Download
DigitalAbacus.zip