Integrating Integers Into the Classroom

Welcome back!

This week's math class was all about integers. This was a unit that I didn't mind too much when I was in school. The rules of adding integers always stuck in my mind. A negative integer plus a negative integer makes a negative integer. A positive integer plus a positive integer makes a positive integer. A positive integer plus a negative integer equals a negative integer. When it comes to subtracting integers, it can become a little tricky. A rule that Sue taught us for subtracting two integers is called KFC.

KFC – Keep the first. Flip the minus sign. Change the second integer to the opposite.

For example, (-4) – (-7) becomes (-4) + 7 which equals 3.

We explored different types of activities that would be interesting to use in the classroom when covering this unit. For one activity called "Stick-it Together", we were provided with a word problem and we had to solve the answer and write it on a sticky note. Once we had our answer, we shared it with the rest of our group members and had to decide on one final solution that we all thought was correct. We then wrote our final solution and answer on a sticky note and stuck it on our worksheet. A lot of us realized that it was a tricky word problem and that we had solved the answer incorrectly because we did not read the question carefully.

Here is an image of our work:

Image by Yasmine Khaizaran

The question reads as follows: Mt.Everest, the highest elevation in Asia, is 29, 028 feet above sea level. The Dead Sea, the lowest elevation, is 1, 312 feet below the sea level. What is the different between these two elevations?

When I read the question, my initial instinct was to subtract the two numbers in order to solve for the answer. I thought because we were looking for the "difference", this meant that I would need to use subtraction. What I didn't realize was that the question states that The Dead Sea is "below elevation", in other words, it is a negative number. The correct way to solve would be to use the KFC method to subtract integers. This would mean keeping the first number (29, 028), flipping the subtraction sign into an addition sign, and then changing the negative number (-1, 312) into a positive number. From there, you would need to add the two positive integers in order to find the answer. As easy as this question was, many of us did not read the question thoroughly through, which caused us to make the slightest error.

This word problem was definitely challenging! It would be a great problem-solving activity to use in the classroom when teaching the integer unit to students.