Get your students coding with simple apps. Programming skills are tied with mathematics and logic. It's a great skill for students to have. Many schools are starting to implement programming in their computer classes beginning in the elementary.
When I taught, programming courses were one of my favorite classes. I loved seeing the student's eyes light up when they understood their code or could find the error they made.
Take a look at the following apps:
LightBot Hour of Code - Android
Cargo-Bot - iPad
Hopscotch - iPad
Code Box - Android
Tynker - iPad