Adding and Subtracting Integers

1. ADDING AND SUBTRACTING
INTEGERS

2. RULES FOR ADDING INTEGERS
• If the integers have the same sign, add them together and keep the
sign.
For example:
10 + 15 = 25
14 + 16 = 30
(-5) + (-7) = -12
(-12) + (-9) = -21

3. RULES FOR ADDING INTEGERS
• If the integers have different signs, subtract them. The sign of the
greater number will be the sign of the answer.
For example:
5 + (-8) = -3
-4 + 11 = 7
(-10) + 15 = 5
10 + (-30) = -20

4. Try this:
1. 45 + (-20) =
2. (-65) + (-40) =
3. (-75) + 20 =
4. 3 + (-1) + 4 + (-7) =
5. -14 + 22 + 8 + (-16) =
25
-105
-55
-1
0

5. RULES FOR SUBTRACTING INTEGERS
1. Convert the subtraction sign into an addition sign.
2. After converting the sign, take the inverse of the number which
comes after the sign.
Once the transformation is done, follow the rules of addition.

6. RULES FOR SUBTRACTING INTEGERS
For example, finding the value of (-5) – (7).
1. Change the subtraction sign into an addition sign.
(-5) + 7
2. Take the inverse of the number which comes after the sign.
-5 + (-7) (opposite of 7 is -7)
-5 + (-7) = -12 (add and put the sign of greater number)

7. Examples:
1. 16 – (-20) =
2. (-19) – (-15) =
3. 53 – 25 =
4. 30 – (-9) =
5. -19 – 2 =
36
-4
28
39
-22

8. Try this!
1. 38 + (-22) + 19 =
2. (-40) + 33 =
3. (-15) + (-27) =
4. 18 + (-11) + (3) =
5. (-4) + (25) + (-15) =
6. (-5) – 9 =
7. -14 – (-34) =
8. 5 – (-12) =
9. (-2) – (-4) – (-6) =
10. (-42) – (-34) – (-9) =
35
-7
-42
10
6
-14
20
17
8
1