I love teaching functions! Students have always understood them because of all the work done with rate of change, point-slope equations and relationships prior. I begin functions with some mathematical dating advice. You can imagine 8th graders' reactions when they see dating advice on the agenda! I have students cut out a paper heart for their interactive notebooks to add to the excitement. Then I write this on the board and ask students what they notice.
Students erupt with girls saying oohhhhs and mmhhhmms as they accuse Drake of being a "cheater" or "low down" or a "dirty boy!" The boys argue he is just a player! I ask why they are upset and lead them to say that Drake is cheating with two different girls. I tell them this is NOT a functional relationship. Through the years, I just change the boy and girl to whoever has the most drama that year! The last couple of years I have used (Archie, Veronica) and (Archie, Betty) from Riverdale and they love that too. They seem to never forget how to tell if a relation is a function or not. And the justifications they use to defend their answers, "-2 is not a function because he is cheating with 9 and 0 and that is more than one output," are priceless!
Once they have practiced with identifying functions from ordered pairs, tables, graphs, and mapping diagrams we are ready for the SUPER awesome FUNCTION AUCTION from Math=Love. Being retweeted by her never gets old! It makes me feel like a math teacher super star!
The prep for this activity is simple with only a couple of things that need to be printed and laminated. I make one copy of the Function Auction Lot Catalog, a bidding paddle and some monopoly money for each group. I also used my Bitmoji to create cards so that I have something to give them at the end of each item's bidding. It made it a little more exciting, especially when it was the garbage can they received!
Students are given $1,000 and five minutes to look over the catalog and decide which ones they want to bid on and work on a strategy as to how they are going to bid. Some groups bid right away, some hold out until the last item and bid all their money. The group with the most functions at the end of the auction wins. If there is a tie, we look at the group with the most money left.
I love watching them strategize and listening to their conversations about which ones they will bid on and how. The Function Auction brings a lot of excitement to our classroom as you can see in the video below.
There is nothing better than a room full of happy kiddos doing math and leaving class talking about how much fun they had in math today!