## Wednesday, October 10, 2007

### Teaching Domain and Range (with a little help from Beyonce)

There are a lot of things in math that are easy concepts to understand, but also easy to forget. Last year, my students had a lot of trouble remembering domain and range. It dawned upon me to write a song to get this idea across for two reasons: music is one of the most powerful (and neglected) learning modalities, and it was something to get my students excited about coming to class.

At that time, one of the top songs in the country was Beyonce's catchy, guitar-driven hit "Irreplaceable". I would hear this on the radio daily, and I had even learned to play it on guitar because I liked it so much. Somewhere in this time, the opening lyrics: "To the left, to the left..." jumped out at me. My students had trouble remembering that when looking at a graph, the domain was from the left to the right. "To the left" became "to the right" and honestly, the rest was easy. I made sure that the most important and basic ideas they needed to know were addressed in the lyrics:
• domain: x-values, left to right on the graph, first number in a coordinate point, always ordered from least to greatest
• range: y-values, up and down on the graph, second number in a coordinate point, also ordered from least to greatest
I introduced the song by asking, "How do you remember the alphabet?" Everyone starts singing the alphabet song and I say "yes, and the reason you were taught this song is not because it's a cute little song but because it is easy to remember. You learned something from this song--isn't it true that you could name me the lyrics to 'Beautiful Girls' quicker than you could explain the easiest things we did in class." This is the idea of the Domain and Range Song.

I sang and played the song on guitar by myself last year, but I wanted it to be a bit more interactive this year to make it even more memorable. Thus I put a few more phrases in boldface and after performing the song once by myself, I asked the students to sing (or at least say) the words in bold in a sing-along. Here, at last, is the now infamous song:
THE DOMAIN AND RANGE SONG
To the tune of “Irreplaceable” by Beyonce

To the right, to the right
To the right, to the right
Everything in the domain from the left to the right

On the graph, domain’s the x
From least to greatest, and here's what's next
I'm talking about the range--that's the y
how far up and down the graph goes at the same time
Put those in order from least to greatest too
So you can answer the questions that I gave you

Sitting in Mr. D's class, thinking bout how he's such a fool,
How we'll never ever forget how to do
domain and range yeah

You must now know domain, you must now know the range
Matter fact, you’ll pass the test in a minute, baby

You must now know domain, you must now know the range