Welcome Activity
Add.
1. 2 + 3 5
3. 8 + 5 13
2. 7 + 4 11
4. 17 + 12 29
Name the integer that corresponds to
each point.
5. A –3
6. B
5
2/2/2016 7-3 C Adding Integers
Adding Integers on a Number Line
Move right on a number line to add a positive integer.
Move left on a number line to add a negative integer.
Writing Math
Parentheses are used to separate addition,
subtraction, multiplication, and division signs
from negative integers.
–2 + (–5) = –7
Example 1
Write the addition modeled on each number line.
+ (–4)
5
A.
–1 0
1
2
3 4
5
6
The addition modeled is 5 + (–4) = 1.
B.
+7
(–4)
–5 –4 –3 –2 –1 0 1 2 3 4
The addition modeled is –4 + 7 = 3.
Example 2
Write the addition modeled on each number
line.
+ (–5)
3
C.
–4 –3 –2 –1
0
1
2
3
4
The addition modeled is 3 + (–5) = –2.
Example 3
Find the sum.
Think:
–3 + (–2)
+ (–2)
–6
–5 –4
–3
–3 + (–2) = –5
–3
–2
–1
0
1
• Take the sign of the LARGER number and
subtract!
Example 4
Find the sum.
Think:
6 + (–8)
+(–8)
6
–3 –2 –1
0
6 + (–8) = –2
1
2
3
4
5
6
7
Example 5
Evaluate y + (–2) for y = 7.
y + (–2) Write the expression.
7 + (–2) Substitute 7 for y.
5
Add.
Example 6
A sunken ship is 12 m below the sea level. A
search plane flies 35 m above the sunken ship.
How far above the sea is the plane?
The ship is 12 m below the sea level and the
plane is 35 m above the ship.
–12 + 35
23
The plane is 23 m above the sea.
Your Turn: Complete and then complete
the next slides.
Find each sum.
1. 7 + (–3) 4
2. –5 + 2
–3
3. –8 + (–4) –12
4. Evaluate x + 5 for x = –4.
1
5. At midnight on a winter night, the temperature
was –12°F. By 10 A.M. the temperature had risen
42°F. What was the new temperature?
30°F
1. Identify the sum. 13 + (–5)
A. 8
B. –8
C. 18
D. –18
2. Identify the sum. –12 + 5
A. 7
B. –7
C. 17
D. –17
3. Identify the sum. –18 + (–5)
A. 13
B. –13
C. 23
D. –23
4. The basement of a building is 10 feet below
the ground level. The height of the building
including the basement is 69 feet. What is the
height of the building from the ground level?
A. 79 ft
B. 69 ft
C. 64 ft
D. 59 ft
@ Home
• Adding Integer W.S. (Front side) All