1. Unit 1: Integers

2.  There are two types of problems:  1- When the signs are the same  3 + 2 = 5  -3 + -2 = -5  2- When the signs are different  3 + -2 = 1  -3 + 2 = -1

3.  Same signs?  Add them together, keep the same sign. 3 + 2 =5 Here, both numbers are positive. So, we just add the two numbers, and keep the answer positive. -3 + -2 = -5 Here, both numbers are negative; so, we just add the two numbers, and keep the answer negative.

4.  Different signs?  Subtract the numbers, take the sign of the bigger number. 3 + -2 = 1 First, we subtract 3-2 and get 1. The bigger number is 3 and it is positive, so our answer must be positive. -3 + 2 = -1We know that 3-2 gives us 1. The bigger number is 3 and it is negative, so our answer must be negative. **When I say “bigger number” I mean the sign with the greater absolute value**

5. -10 + -10 = ______ -10 + 5 = ______ 6 + -1 = ______ 15 + 5 = ______ -20 -5 +5 +20 Since both numbers have the same sign, we add them together, and keep the same sign. 10+10=20, and they are both negative, so our answer is -20 Both numbers have a different sign. Therefore we subtract: 10 – 5 = 5. Since 10 is bigger than 5, we keep the sign from 10, which is negative. Both numbers have different signs, so we have to subtract: 6-1=5. The bigger number is 6 and it’s positive, so our answer is positive. Both numbers have the same sign, so we add them together: 15 + 5 =20. Since both numbers are positive, our answer must be positive. Complete these four problems, then click the mouse for the answers.

6.  Need more help? Try this technique -8 + 5 = _______ We have a negative 8 and a positive 5, let’s draw this out: NegativePositive -8 +5 Next, for every positive we have, let’s take away a negative… Finally, we see that we only have 3 left in the negative box; so our answer must be -3

7.  Another technique is to draw a number line: -8 + 5 = _______  ---I-----I-----I-----I-----I-----I-----I-----I-----I-----I-----I------I------I------I------I------I----  0 -2-3-4-5-6-7-81235467 Start by tracing back to -8Then, from -8, trace forward +5 So our answer must be -3

8.  That’s it! Here are some more practice problems to try… -10 + 8 = ____ 5 + 7 = ____ 7 + -10 = ____ -6 + -4 = ____ 8 + -6 = ____ 4 +-10 = ____ -5 + 5 = ____ -5 + -5 = ____ -2 12 -3 -10 2 -6 0 -10

9.  This has been a Rockin’ Presentation by: Mr. Lattyak