This is a set of 24 task cards designed with the question in mind:
Is it a function?
I would print these cards (with the shorter side being the flipping side) on cardstock and cut. The students will be able to go through the 24 cards and answer Yes or No (and why!) to the question of the relation being a function.
Half of each set is a function and the other half is not. You can also have students match the table to the mapping to the graph as an additional focus to show how the functions and non-function relations have similarities!
Please note- these cards are the same as my relations cards in my TPT store, HOWEVER - the relations card set has more and only is made for matching reasons. Those have nothing to do with determining if the relation is a function.