It's a Ministry video, produced in a combined Grade 6/7 class. Several groups debrief their solutions to a problem involving proportional reasoning (curriculum connections here). I struggled with the first few, because the solutions produced "incorrect" responses... Why is the teacher spending so much time on the wrong answer, I wondered?!
But then the teacher's brilliance shines through:
From here, students are given an opportunity to consider this new bit of information. Both dogs (in the problem) grow 3 kg. But the second dog doubles its weight, while the first dog just gets 3 kg bigger.
Once the students have a chance to chat about this, the teacher -- rather than confirming which solutions are "correct" -- has students independently complete an exit ticket telling what they think. In this way, the teacher is able to ascertain what individual students know and understand about proportional reasoning, and more specifically, multiplicative thinking/doubling. But not until they've all had the chance to benefit from the collective learning of the class.