Do you have students that don't talk during the argumentation session?  Try using our Math Back Pocket Question Cards.

Carry this set of cards with you as you move from group to group.  When you see a group that is not talking, hand one of the cards to one of the students who is responsible for critiquing the argument. Once the students are talking, take back the card and move to the next group.

Each set includes 16 cards total, measuring 3.5” x 2.5”.