This Activinspire flipchart allows you to model subtracting mixed numbers where students would need to regroup using the whole number. Physically be able to show the regroups with fraction circles along side the standard algorithm.
How to use:
1. Drag the circle with blue pieces to Garbage to reveal
equivalent fraction with the common denominator.
2. Drag the yellow circle with the black dot to Garbage to
represent regrouping a whole for fraction parts.
3. Drag blue fraction pieces and yellow circles to Garbage
can to model subtraction.
I have used the Dual User tool to have one student move pieces and another (or myself) to model the traditional algorithm.