Systems using elimination

Let me just say, wow!  The Internet is amazing!  I posted that silly donors choose video and bam I have classroom supplies coming straight to my door.  The blog had taken to the back burner, but I am back with a few posts.  I am going to do two today, the first for my Algebra class, the second for math tech 3/geometry.

I find that substitution is a difficult method to follow out of the three.  Unless you are a math nerd like I was in high school and had plenty of experience with math relays.  So finally, we come to elimination!  I think out of the three forms, minus the calculator for graphing, that this is the easiest form to solve for students.  I showed the students how to find the lcm in the calculator (a trick I didn't learn until I went back to school for my master's degree).  Go to ALPHA then over to the right to NUM and voila!  This menu can factor using the gcd, find the lcm, and plug the absolute value into your calculator.  I mean really, why did I not know about this?!

So after teaching the method, I used these worksheets from online.  There was one error on the substitution package, but the elimination seemed to be perfect.  I had students do the cut out activity as the students homework after the notes were taken.  I love this packet because it breaks the material down into steps.  The second can be used as a gallery style activity (the way I presented it) or as a matching activity.  I loved it!  The kids seems to really catch on using elimination.  I heard a few complaints from them about the number of steps needed to solve the equations.  We are playing a review game and quizzing on the three methods prior to teaching them how to just use a matrix.  Man do kids always get mad.  "Mrs. P, why did you make us do the other forms?  The matrix is soooo easy."

Note: there are limits to using the lcm or the gcd...you can only plug in two numbers and you must keep them positive.