Sharon B and Gaumy (and anyone else!)
I used 2 1/2 inch WOF strips sewn together in sets of 6. 4 sets of 6 gives you a 3ft long runner and 6 good sized mats.
In each set I ALWAYS have a white and probably a 'plainish' green or red. The rest are split between holiday prints.
After piecing each set we cut across at 2 1/2 inch and reorder the strips and sew.
The layer and quilt, we used extra random Chrstmas prints cut into 2 1/2 inch strips for binding. Very good fun!
Hope that helps!! Saves you a few minutes doing the maths ayway!!