Download Adding Integers with the Same Sign

ADDING
INTEGERS
4, -7, 0, -9, 7
What do these numbers have in common?
What do -7 and -9 have in common? How
do you know this?
What do 4 and 7 have in common? How
do you know?
How are the integers -7 and 7 related?
TODAY’S DEFINITIONS
• OPPOSITES: Two integers are opposites
if they are represented on the number
line by points that are the same distance
from zero, but on opposite sides of zero.
The sum of two opposites is zero. (Ex. 1
+ -1 = 0)
• ADDITIVE INVERSE: The opposite of an
integer. The sum of an integer and its
additive inverse is zero.
Give an example of
integers that are
additive inverses!
Adding Integers with the
same sign
• The sum of two positive integers is
positive!
Example: 1 + 1 = 2
• The sum of two negative integers is
negative!
Example: -1 + -1 = -2
• **YOU CAN USE A
NUMBER LINE TO ADD
POSITIVE AND NEGATIVE
NUMBERS
Add the following integers
•Find -4 + -8
•Find -6 + -2
•Find -15 + -9
•Find 2 + 10
Counter Activity: Adding
Integers with the Same Sign
1. -9 + -7
2. -14 + -3
3. -5 + -17
4. 2 + 16
5. -7 + -17
Adding Integers with
Different Signs
• The answer will be positive if the
LARGER number is positive!!!
Example: 5 + -3 = 2
***The larger number is five, so the
answer is positive.
***You always subtract the larger number
from the smaller number. 5 is larger
than 3, so,
5 + -3 = 2
Adding Integers with
Different Signs
• The answer will be negative if the
LARGER number is negative!!!
Example: -5 + 3 = -2
***The larger number is five, so the
answer is negative.
***You always subtract the larger number
from the smaller number. 5 is larger
than 3, so,
-5 + 3 = -2
Number Sense
• Tell whether each sum is positive,
negative, or zero, WITHOUT
ADDING!
1. -6 + (-7)
2. -8 + 10
3. -14 + 14
Adding Integers with
Different Signs
•Find -4 + 8
•Find -6 + 2
•Find -1 + 9
•Find 2 + -10
Brooke and Javier are finding
-12 + 13. Who is correct? Explain.
Brooke’s Work
-12 + 13 = 1
Javier’s Work
-12 + 13 = -1
Counter Activity: Adding Integers
with the Different Signs
1. -9 + 7
2. 14 + -3
3. 5 + -17
4. 2 + -16
5. -7 + 17
Advanced: Write an addition
expression to describe each situation.
Then find each sum.
1. The weather outside is -3 degrees. The
temperature drops 6 degrees.
2. A submarine dives 106 feet below the water.
Then, it rises 63 feet.
3. Jace starts at the bottom of a half pipe 6 fet
below street level. He rises 14 feet at the
top of his kickturn.
4. Stephanie has $43 in the bank. She
withdraws $35.
Advanced: Evaluate each expression
if x = -10, y = 7, and z = -8
1. x + 14
2. 6 + y
3. z + -5
4. -17 + y
5. x + z
6. x + y + z
Advanced: Simplify
1.x + -5 + 1
2.4 + y + -2
3.-9 + m + (-6)