Rules to Subtract Integers
The rules for subtracting integers can be confusing for some students. This is a quick and easy method to subtract integers.
K C C
KEEP CHANGE CHANGE
Why does the KCC method work every time we subtract integers? It works because we are adding the opposite. You may remember this reference from middle school math.
Let’s Subtract Integers!!!
Step 1. Write the problem with a little space in between the integers and the subtraction sign. It will help you line up the KCC underneath.
Step 2. Write the letters KCC in that order underneath the subtraction sentence.
Step 3. Follow the KCC method. Keep the first integer the same. Change the subtraction sign to an addition sign. Change the sign of the last integer.
Step 4: ADD!! That’s IT!
Example 1:
-4 - 8 =
In example one, the -4 stays the same: WE KEEP IT. The subtraction sign changes to an addition sign: WE CHANGE IT. The 8 changes to and -8: WE CHANGE IT. Lastly, add -4 and -8 which equals -12.
Example 2:
-12 - (-7)
In the subtraction problem, the -12 stays the same: WE KEEP IT. The subtraction sign changes to and addition sign: WE CHANGE IT. The -7 is changed to a +7 WE CHANGE IT. Lastly, add -12 and 7, which equals -5.
Guess What?? That is it! You have learned how to subtract integers with the KCC method.
Subtracting Integers Notes for Algebra Readiness
Now it’s your turn. Try out these problems. Check your answers.
1. -5 - 7 =
2. -8 - 8 =
3. 17 – (-9) =
4. 8 - 10 =
5. 12 - (-4) =
Solutions
1. -12 2. -16 3. 26 4. -2 5. 16
The best way to get better at any math skill is to practice. It takes someone between 15 and 30 repetitions, to master a skill. I have given you a couple of examples and practice problems. Some students need a lot of practice to grasp integer operations. For more review on subtracting integers and all the skills that you need for Algebra 1, watch the videos on my Instagram page or go to my website, maryiverstine.com and schedule a free consultation.
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Mary Iverstine specializes in tutoring algebra and geometry to students in middle school and high school. When Mary is not tutoring students or studying mathematics, she loves to spend time with her husband, two children and two dogs.