I like to introduce my students to sets because it helps talk about other concepts (like functions) more easily. This is a first day of class activity that allows students to get to know their classmates and use sets at the same time. The first page is notes filled out, the second page is notes that are not complete (the students should fill in), the third page is the group activity (I would have them work with one other partner for 2 minutes and decide what set that person belongs to for all the questions and then switch partners so everyone works together. Give more time for the first pairing and as they get use to the process speed it up). Finally there is homework or it could be individual work afterwards that introduces students to the size of a set. Along the way students will encounter basic facts like what makes a number even, is 1 prime, etc. All in all, this could be a nice day 1 activity for your class. I have left it as a word document so you can easily edit it to meet your needs and change the headings of each page if you need to do so.