This sampling set of 3 task cards focuses on the skill of determining whether or not a relation is or is not a function and why.
You can find the complete set of 30 task cards for $2.00 at:
Functions & Relations Task Cards Set of 30
Examples include graphs, tables of values, and mapping diagrams.
The cards can be used in a whole group, small groups, or as a math center. They are a great resource for remediation and extra targeted practice.