## Tuesday, June 12, 2012

### Exam notes: Integer Subtracting tips (without calculators)

I am going to show you tips on how to make subtracting integers easier.

First of all, I would list questions that you have to solve in the end of the blog:

1.) 19 - 79 = ?
2.) 95 - (-54) = ?
3.) (-98) - (-94) = ?
4.) (-78) - 85 = ?

Now, to solve these, it's going to be hard because of the large numbers right? So, we can use this strategy: opposite operations. The way that the opposite operations strategy works is that you switch the sign of the number on the right and the operation.
e.g.  3 - (-4) can be converted to 3 + 4 so that finding the answer is easy, instead of wasting time trying to use integer chips (which is another strategy).

So now you understand how to use the opposite operations here's a list on the possibilities:
a) (-) - (-) = (-) + (+)
b) (-) - (+) = (-) + (-)
c) (+) - (+) = (+) + (-)
d) (+) - (-) = (+) + (+)

Now I hope you got it! AND DON'T FORGET TO ANSWER THOSE QUESTIONS! Except for you Mr. Isfeld.