During our first Algebra 2 unit on functions, my students have been evaluating a lot of functions. They fully understand the concept of substituting in the given value of the variable. However, so many of my students do not place the value in parentheses when they substitute it into the function. Most of the time, they still end up with the right answer. But, they always end up missing problems such as find f(-2) if f(x) = -x^2 - 2x + 4. When they substitute in the -2 without parentheses, many of my students' first instinct is to change the two negative signs to a positive sign. This is bad. Very bad.
I don't know about you, but I have a terrible time convincing students that the way they have been doing algebra for the past few years is wrong. I can tell them it is wrong. I can hand back their graded papers that are covered with ink. We can review it as a class. But, for some reason, they seem to instantly tune me out as soon as they realize this is something they have already learned before, even though they did not learn it correctly in the first place.
This year, I decided that my Algebra 1 students were not going to follow in the footsteps of my current Algebra 2 students. When my students evaluated expressions or functions, they were going to always, always, always use parentheses. I asked myself, "How can I accomplish this?" I thought about the way I normally emphasize things in my classroom. I say them over and over and over. I write them in all caps with plenty of underlining on the Smart Board. I have my students write it in their notebooks. I repeat myself constantly.
That just didn't seem quite special enough. Those methods are just a normal day in my classroom. I emphasize a lot of stuff. So, how could I really emphasize something? How could I teach like a pirate? How could I give my students an experience instead of just another math lesson? The answer didn't come quickly.
In fact, it came as an epiphany about fifteen minutes before class was supposed to start. I wasn't going to just tell my students that they should always use parentheses when substituting values into an algebraic expression. No, my students were going to tell me that they would always use parentheses when substituting values into an algebraic expression.
I quickly typed up an oath: I, _______________________, do solemnly swear (or affirm) that I will always use parentheses when substituting values into an algebraic expression. To complete the experience, I printed the oath on gray card stock. I made lines for my students to sign and date. When cut out, the oaths would be conveniently wallet-sized so students could be reminded of this oath forever. (Students who were uncomfortable with taking an oath or swearing were given the option of affirming the statement instead. By saying that they affirmed the statement, they would be making an affirmation instead of an oath.)
|Algebraic Oath Card|
I used all of my acting skills to really play up this oath. I told the students how serious of a matter this was. I passed out the cards with the oath printed on it. I asked students to read the oath to themselves and see if they had any questions about the commitment they were preparing to make. Next, I made my students stand up. I chastised them for not taking this experience seriously enough. I had them raise their right hands. There were giggles and smart comments. Again, I reminded students that this was a very serious matter. I told them that the fact that they were not taking this as seriously as they should be was "crushing my heart."
In unison, we read the oath together as a class, and we signed our cards to commemorate the occasion. My students pointed out that there should have been a place on the card for a witness to sign... Some of my students suggested that we should have placed our hands on our interactive notebooks when we took the oath. I heard several students say that they felt like they had just joined a gang. Apparently, they now look at me as their ringleader.
There were the students who thought the entire thing was stupid. They told me that they were going to bring their cards to graduation and burn them in front of me. But, for the most part, I think my students really enjoyed it. I love the fact that sometimes the only help I have to give a student is to ask them, "Remember the oath that you took?" One of my students, when he turned in his homework, said, "I think I got all of my problems right because I remembered my oath."
I've uploaded a pdf version of the cards here, but I'm not entirely happy with it. I whipped up these cards in less than five minutes, and it definitely shows. But, I think they served their purpose.