ADDING INTEGERS

1. Rules Examples
Adding integers with the
same sign
The sum of two positive
integers is always positive.
The sum of two negative
integers is always negative.
6 + 2 = 8
(-6) + (-2) = -8
Adding integers with different
signs
If the numbers you are
adding have different signs,
subtract the smaller number
from the larger number, then
determine which number is
larger.
The sign (positive or negative)
of the answer will be the sign
of the larger number.
8 + (-2) = 6
(-8) + 2 = -6

2. ADD INTEGERS
What is an integer?
Integers are just whole numbers
Integers can be negative
• A number less than zero
• Express ideas of down, a loss or a
debt
• The sign for a negative integer is
(-), however this sign is always
needed
• Numbers like -3 or -5
Integers can be positive
• A number greater than zero
• Express ideas of up, a gain or a
profit
• The sign for a positive integer is
(+), however the sign is not
always needed
• Meaning +3 is the same value as 3
• Numbers like 5 or 6

3. ADD INTEGERS When are Integers Used?
We use integers when we deal with temperature.
Especially when it’s really cold.
We use integers when we use dollars. Have you
ever “owed” anyone money before?
We will use integers a lot when we deal with
algebra and graphing. They help us navigate
when we are on a grid.

4. ADD INTEGERS How do we add positive
and negative integers?
The sum of two positive integers is always positive.
If the Beginning
Signs Are . . .
Then the Calculation
we do is . . . .
The End Sign of our
answer is . . . . Example
SAME ADD SAME 3 + 1 = 4
3
1
Start at 0. Move 3 units to the right to
show +3. From there, move 1 unit to the
right to show +1.

5. ADD INTEGERS How do we add positive
and negative integers?
The sum of two negative integers is always negative.
If the Beginning
Signs Are . . .
The the Calculation
we do is . . . .
The End Sign of our
answer is . . . . Example
SAME ADD SAME 3 + 1= 4
-1 Start at 0. Move 3 units to the left to
-3
show -3. From there, move 1 unit to the
left to show -1.

6. ADD INTEGERS How do we add positive
and negative integers?
If the numbers you are adding have different signs, subtract the smaller number
from the larger number, then determine which number is larger.
The sign (positive or negative) of the answer will be the sign of the larger number.
If the Beginning
Signs Are . . .
Then the Calculation
we do is . . . .
The End Sign of our
answer is . . . . Example
DIFFERENT SUBTRACT The Sign of
the Larger
Number.
3 + 1 = 2
3
-1
Start at 0. Move 3 units to the right to
show +3. From there, move 1 unit to the
left to show -1.

7. ADD INTEGERS How do we add positive
and negative integers?
If the numbers you are adding have different signs, subtract the smaller number
from the larger number, then determine which number is larger.
The sign (positive or negative) of the answer will be the sign of the larger number.
If the Beginning
Signs Are . . .
Then the Calculation
we do is . . . .
The End Sign of our
answer is . . . . Example
DIFFERENT SUBTRACT The Sign of
the Larger
Number.
1 + 3 = 2
-3
+1
Start at 0. Move 3 units to the left to
show -3. From there, move 1 unit to the
right to show +1.

8. ADD INTEGERS
7 + 8
1. We are adding and the numbers have
same sign.
2. Add
7 + 8 =
ANSWER:
15

9. ADD INTEGERS
20 + 5
1. We are adding and the numbers have
same sign.
2. Add
20 + 5 =
ANSWER:
25

10. ADD INTEGERS
8 + (-2)
1. We are adding and the numbers have
different sign.
2. Subtract
8 - 2
ANSWER:
6 or +6
3. 8 is larger than 2
4. Since 8 is larger and
positive , the answer will
be positive

11. ADD INTEGERS
(-8) + 2
1. We are adding and the numbers have
different sign.
2. Subtract
8 - 2
ANSWER:
-6
3. 8 is larger than 2
4. Since 8 is larger and
negative , the answer will
be negative

12. ADD INTEGERS SUMMARY
The sum of two positive integers is always positive.
20 + 5 = 25
The sum of two negative integers is always negative.
20 + 5 = 25
If the numbers you are adding have different signs, subtract the smaller number
from the larger number, then determine which number is larger.
The sign (positive or negative) of the answer will be the sign of the larger number.
8 + (-2) = 6 (-8) + 2 = -6