User enters text backwards for math problem

I am working on a simple math game for kids. It is nearly complete but the problem I have is that when the user enters their answer in the input textfield, the numbers are entered from left to right. Most people do math problems from right to left. Is there a way to make the numbers appear from right to left? I am thinking that I would have to use an eventlistener on the number keys and also use parse text or arrays somehow to manipulate the numbers. But I am hoping there is an easier way. Any ideas?