Perpendicular Lines Alg 1 #VNPS

Just did another 20 minute board problem in Accelerated Algebra 1 after lunch.  They are getting so good and going straight into their board groups after lunch and instantly starting.  Today, I used an Open Middle problem I saw on Twitter.  They attacked it different ways, some drew the problem with boxes, some started listing numbers 0-9 and then the fractions, some drew the graph.  I love watching as they look around the room to see what other groups are doing.  I had one group get it pretty quickly and they just naturally went to help some other groups, not by telling them the answer, but by giving them clues or asking them leading questions - natural teacher moves.  Yeah VNPS again!