Download 1.1 Notes: Adding and Subtracting Integers

1.1 Notes: Adding and Subtracting Integers
There are three rules to help us combine numbers.
 Positive + Positive = Add the numbers and keep the
sign of the larger number.
 Negative + Negative = Add the numbers and keep the
sign of the larger number.
 Positive + Negative = Find the difference and keep the
(or Neg + Pos)
sign of the larger number.
We need to remember these rules. Let’s try a few example…
1. 15 + 17
2. -12 + (-10)
3. 7 + (-12)
4. -4 + 7
5. 4 – 20 + 6
6. -3 – 11 + (-6)
Another situation that will come up is when you subtract a negative
number. It is important to remember to convert that into addition.
10 – (-5)
10 + 5 (the two negative signs = addition)
15
Let’s try a few examples…..
7. -3 – (-4)
8. 5 – (-12)
9. -20 – (-30) + 10
10. -6 – (-5) + 4
11. 3 – (-10) -6
12. -10 – (-6) – 3
(Stop and wait for teacher.)
POS  POS = POS
NEG  NEG = POS
POS  NEG = NEG
POS
NEG
POS
 POS = POS
 NEG = POS
 NEG = NEG
1. 4(3)
2. (-5)(10)
3. (-10)(-5)
4. (7)(-4)
5. (8)(8)
6. (-11)(-4)
7.
10.
20
4
16
2
13. (-2)(-3)(5)
15.
(6)(2)(2)
4
8.
11.
36
6
9.
25
5
10
40
12.
14. (6)(-2)(4)
16.
2
(4)(3)(1)
49
7