Students will work in pairs/partners to identify the constant rate of change and whether the function is proportional.
Each Partner will find the constant rate of change for their table. They will then compare their answers. If they do it correctly they will have the same answer. If the answers 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.