Did you know that Augustana College has a number sense project? They sent their university students into the schools to work with kindergartners. This morphed into a series of educational apps to build number sense. The apps are not super fancy, but they do focus on building number sense with ten frames, subitizing, and number lines.
Here is the list I am hoping to purchase for our iPads at school.
Line 'em Up Free
10 Frame Fill Free
What's Hiding? $0.99
Word Problems Free
Thinking of a Number $0.99
Pattern Sets $0.99