Math Mountains: Add & Subtract

This app helps you learn your math facts by creating fact families in the shape of mountains. There are two modes in this app -- Explore and Practice.
Explore
The sum (greatest number) is at the top of the mountain and the related facts are at the bottom. Enter numbers in the circles to create and solve problems of your choosing. When a correct fact family has been entered, the circles will display as green. If the numbers do not form a correct fact family, the circles will display as red. Numbers can be changed as much as needed, and a user can also reset the screen to start over.
Practice
Choose the fact(s) you want to practice. Then select the number of problems. The timer can be turned on or off - it is not a countdown timer, it keeps track in the background and gives you the time to complete your practice set on the results screen. When a practice set is done, you can choose to redo it with the same settings, change the settings, or change back to Explore mode.