Math = Love: Integer Operations Posters

Sunday, October 21, 2012

Integer Operations Posters

For over a month now, I've been meaning to set down and create a set of posters that summarize the rules for integer operations to hang in my classroom.   Today, I finally did it.

At one point in the semester, I had these written out on my dry erase board.  I never saw anyone use them, so I decided to erase them when I cleaned my board.  The next day, I had several students questioning me about where the rules had gone.  So, I rewrote them on the board.  A week or two later, my computer and Smart Board decided to stop working.  No Smart Board means I have to use the dry erase board.  So, I ended up erasing the rules again.  And, again, I heard from several students who wanted to know where the rules had gone.

They've been erased for a while now with no more complaints, but we're getting ready to start graphing using a t-chart.  So, I wanted to create a permanent place in my classroom to post a short reminder of the rules.  It is my goal that by the end of the year all of my students will know these by heart.  But, until then, I want them to have a place to look when they can't remember instead of just guessing.

Here are the posters I created.

 Integer Operations Posters
These aren't arranged exactly as I want them, but I'm going to live with it.  I'd planned to hang the title poster on top.  But, that's not going to happen.  You see, I have two options.  I can either live with this arrangement or I can carry a ladder up the stairs to the second floor.  And, I just can't justify toting a very heavy ladder up a flight of stairs to arrange a few posters.  Now, when I finally get all of my large posters laminated, I may bring up the ladder and hang everything exactly where I want it.  But, until then, this will do.

Download files here.

2 comments:

1. but if there are three negatives multiplied together ....they have the same sign but the answer is not positive. My sixth graders arrived saying that if the signs were the same the answer needed to be positive. We did some hands on with a 'sea of zero' and discovered it wasn't true. Maybe an asterisk is needed on the multiply/divide posters

2. I use even and odds in my definition of multiplying integers. 0 or 2 negatives make a positive, one negative makes a negative. Give them a series of problems with (2)(-2) and (-2)(-2) and (-2)(-2)(-2), and have them figure out the pattern.

I also explain it in lecture with a red/yellow counter chip "coin" that we have for integer ops. Negative means "opposite of" and is represented on the coin by a flip from yellow to red, and so the opposite of the opposite is a flip of a flip, back to yellow. Flipping the coin from positive yellow to negative red to positive yellow, etc, gets them picking up on those patterns that will be so useful once they hit imaginary numbers!!!