Students will work in pairs/partners to identify the slope, type of slope (P=positive, N=negative, 0=zero, U=undefined) and whether the function is proportional.
Each Partner will find the slope for their table. They will then compare their answers. If they do it correctly they will have the same slope. If the slope are different they should justify their answers until one of them realizes their mistake.
This allows the students the opportunity for practice and satisfies their need for instant feedback. I hope your students enjoy this activity.