Adding Integers

Introduction

Adding integers is one of my favorite topics to teach in 7th grade math. After teaching the real number system and additive inverse (sorry, not my favorite) it is fun to teach a concept that is a little easier for students to relate to AND for teachers to make hands on. I like to teach adding integers with manipulatives, both physical and virtual, to help give a visual representation and then I use a fun comic strip to help teach the actual rules of adding integers.

Notes

I like to begin teaching the concept by using two different visual models: counter chips and a number line. First, I start with the counter chips. I use the plastic chips that are red on one side and yellow on the other. I ask all students to go grab a handful and bring them back to their desks. We spend a few minutes modeling various adding integer problems placing important emphasis on zero pairs and how one negative and one positive create a sum of zero (oh yeah, it's the additive inverse property we just talked about the other day). After using the chips to help visualize a few problems, we then practice a few problems on their notes. I use digital notes, so students have various open and closed circles on their computer that they can move around the screen to represent the problem.

After modeling problems using integer chips, we move on to the number line. I have modeled the number line in a variety of ways. We have created a huge number line on the floor of my classroom, drawn a big number line on my board, worked with a printed number line placed in a clear page protector and just worked with a virtual number line on their computer. No matter the method, it is important to put emphasis on the fact that when adding positive integers you will move to the right and when adding negative integers you will move to the left. I would recommend adding in the real-life connection of a football game and how players move up and down the field gaining and losing yards along the way.

Finally, we spend a good chunk of class talking about the actual rules of adding integers. Now that we have modeled on a number line and using counter chips, how would we solve a problems with larger values and without the use of manipulatives? This is where I bring in my comic strip, "The Epic + True Story of Adding Integers."

I use this comic strip to introduce the rules of integers. I am always OVER DRAMATIC when going over the comic strip. We talk about Integer World and how there are negative people and positive people. They are always talking smack and tensions were high. One day they decided to join forces and then battle each other. Three positives (+3) decided to battle two negatives (-2) and after a HUGE battle only one positive remained. Have fun with it! This graphic is available, for free, in my shared google drive. You can access it below.