My first answer would be: do just the same and have them go through one by one. :)
How about writing their names on a piece of paper and getting "them" to step through?
Nope... look closely at the procedure (on the TS) and try to think of a way to fit the whole group in it...
OK, one more try: to fit in all the 12 kids in a row, we have to make the perimeter bigger. Since only the cut parts can make the difference, we must make more cuts. Not really 12 times bigger (i.e. 12x14-1=168-1=167 cuts), because they don't have to be surrounded each by the paper strip.I think we need to know what shape are your kids in section: round, square, rectangular? :)
You are totally on the right track. To make the hole bigger you have to have more cuts! How many cuts there should be isn't interesting, just the idea that you theoretically could fit this whole group in the card! Or in fact, our whole school, or in fact ..... (we can go on for ever!)
That was easy, we feared we had to specify the number of cuts and had started thinking of ways to position to group to get the best result! :)