1. Adding integers

2. When adding integers and the signs are the SAME:
ADD THE NUMBERS TOGETHER
KEEP THE SIGN

3. EXAMPLE 1
9 + 11= 20

4. -9 + -11= -20 2 EXAMPLE Think: I owe you $9 and I owe you $11,
So I owe you $20 altogether.
EXAMPLE 2
-20 =

5. EXAMPLE 3
111 =

6. -111 -98 + -13= 4 EXAMPLE Think: I owe you $98 and I owe you $13,
So I owe you $111 altogether.

7. When adding integers and the signs are DIFFERENT:
SUBTRACT THE NUMBERS
USE THE SIGN OF THE LARGER NUMBER

8. 2 -9 + 11= 1 EXAMPLE Think: I owe you $9 and I HAVE $11,
So I pay you $9 and have $2 left.
EXAMPLE 1 2 =

9. Now, remove the matches:
LET’S
TRY IT
WITH
PICTURES!
This represents -9 =
Add 11 + + + + - - - 2 = + + + + - - - + + + - - -
Now, remove the matches:
1 + and 1 - = 0

10. 9 + -11= -2 2 EXAMPLE Think: I have $9 and I OWE $11,
So I pay you $9 and still OWE $2.
EXAMPLE 2 -2 =

11. LET’S
TRY IT
WITH
PICTURES! =

12. Now, remove the matches:
This represents 9
Add
-11 + + + - - - - + + + - - - - -2 = + + + - - -
Now, remove the matches:
1 + and 1 - = 0

13. EXAMPLE 3
-85 =

14. EXAMPLE 4 85 =