How I Use It
This app would be great for students who need extra practice learning and remembering basic math facts. The game is easy for engagement, similar to Tetris with falling bricks, and does allow opportunity for critical thinking as students are rewarded with additional points for complex combinations. In the classroom, this app could be used as an enrichment activity for students who finish their work early, or as individual practice for a student struggling with a specific sum (e.g. All numbers that add up to 12). I would not use this app with a child who easily frustrates with time limits or losing challenges.
As a teaching tool, I think the greatest frustration is that I couldn't find it in the Apple App Store for iPads (only available for iPhone despite the website disclaimer that it was a multi-device app.) The disadvantages of this app include set sums (4-12); it would be nice to be able to add in your own sum to provide a great range for differentiation. I also had to discover on my own that once you select a digit for an addend, you couldn't unselect that number. The only way you could start again was to go over the desired sum which would allow you to tap a different digit.
That being said, I think it has potential for use in a BYOD classroom using iPhones, but it's limited in that you can only practice addition. While a fun and engaging app, my score reflects the limited appeal for elementary/secondary students overall.