In your small groups, solve problem #7 on the whiteboard. Points for solving and points for the right answer.The groups, which have worked together for six weeks, begin the process at their tables and then begin streaming to the board to get the material displayed.
5 groups do the solution properly and 4 have the right answer at the end. The sixth group's work doesn't resemble any of the others, different numbers, different equations, but the same answer as the 4 groups who got the right answer..
After they're done I go through the first 5 and show where they did things well, especially noting excellent displays of their solutions. Every group gets 5 points, except for the 5th group, which gets 3 points for good work, but not the extra 2 for the right answer.
I write a zero underneath the 6th group.
Group Six Member One: "Wait, why didn't we get any points?"
Group Six Member Two: "Yeah, we got the right answer."
Me: "Which problem did you solve?"
Another group member: "They did the wrong problem."
Group Six Member Three: "We did problem #8."
Me: "Yes," I said. "But that wasn't the assignment."
Group Six Member Four: "Don't we get partial credit?"
Me: "For doing the wrong problem?"
Group Six Member One: "But we got the right answer."
Me: "And how did you get it?"
Group Six Member Two: "We copied it off the other groups."