Operations with Integers

​You might have the "rules" memorized already, in which case, great!!! If not, here are a few scenarios to help you make sense of these problems

• You can think of these in terms of money - you have money (positive) or you owe money (negative)

  • ​-5 + 12 - If I owe $5 to a friend, but I have $12, how much do I have in all?

  • What would this mean? ​-7 + (-3)

  • ​This? 20 - 40

I like to remember SAME, SUM and DIFFERENT, DIFFERENCE:

• if they have the SAME SIGN, you add the values and keep the sign (positive + positive = positive, negative + negative, or negative - positive = negative)

• ​if they have DIFFERENT SIGNS, you subtract the values and keep the sign of the greater value

​You might have memorized that minus a negative turns into a plus...for instance 5 - (-5) can be rewritten as 5 + 5...but have you ever seen a scenario explaining why???

• ​With money, we can think of this as taking away debt, which is basically the same as earning money.

  • ​20 - (-10)

• ​If that's confusing to you, maybe seeing this demonstration of a hot air balloon will help you make sense of minus negative problems

  https://www.geogebra.org/m/CSb4Zq8P

  • ​-2 - (-2)

​You can memorize these rules pretty easily, but until you have it mastered, feel free to use the triangle as a tool!

• ​-2 * 4

• ​-18 / -6