Chris Hunter writes on his blog about a student explaining how they would express 0.500 using ten-frames:

One student expressed this as 500/1000 and 0.500. I assumed he was just extending the pattern(s). “Yeahbut where do you see the 500 and 1000?” I asked challenged. “I imagine that inside every one of these *points to a dot* there is one of these *holds up a full ten-frame*,” he explained. As his teacher and I listened to his ideas, our jaws hit the floor.

Have you seen examples where students come up with innovative ways of representing numbers?