Topic: Number Battle Question

Once you comlete all the challenge missions, is there any way to replay the missions without starting a new game?

EDIT: OK, that's REALLY WIERD. I remember playing through all of the missions on a previous file, and when I clicked on Challenge, it would bring me to the credits. However, my mom just completed another file, and when she clicked on Challenge, she was able to keep playing. WTF?

I'm able to replay levels. However, every time I beat the last level it runs the credits (so I restart before the end.)