Student Instructions
                    Tap the lesson to learn how to use the cows to subtract.
Tap 
 to get started.
Tap the play button to hear the cow tell about the problem.
Use the 
 tool to write out your problem.
Use the 
 tool to move the cows to solve.
Tap the 
 on the right to try the next problem.
Tap the 
 to turn your work in.