Adding Integers Using a Number Line

You start at the origin or zero. Adding Integers You start at the origin or zero. Positive numbers move to the right. Negative numbers move to the left. Origin (Start) -6 -5 -4 -3 -2 -1 1 2 3 4 5 6

Adding Integers = -2 -4 + 2 Start at the origin and move to -4 Then move to +2 Where you finish is your answer Origin (Start) -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 -4 +2

-4 + 2 = -2 Negative = Down Positive = Up Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 -4 + 2 = -2 Negative = Down Positive = Up Elevator Entrance Using a vertical number line is easier to relate to since most of us have been in an elevator! -4 +2

Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 Watch the direction of the elevator when we do integer problems with the SAME SIGN! Elevator Entrance

Adding Integers 8 1) +3 + 5 = +5 +3 Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) +3 + 5 = 8 +5 +3 Elevator Entrance

Adding Integers 8 5 1) +3 + 5 = 2) +1 + 4 = +4 +1 Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) +3 + 5 = 8 2) +1 + 4 = 5 +4 +1 Elevator Entrance

Adding Integers 8 5 -5 1) +3 + 5 = 2) +1 + 4 = 3) -2 - 3 = -2 -3 Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) +3 + 5 = 8 2) +1 + 4 = 5 3) -2 - 3 = -5 Elevator Entrance -2 -3

What do you notice about the direction of the integer elevator? Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 What do you notice about the direction of the integer elevator? 1) +3 + 5 = 8 2) +1 + 4 = 5 3) -2 - 3 = -5 Elevator Entrance 4) -3 - 4 = -7 -3 -4

A positive plus a positive travels up up. Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) +3 + 5 = 8 A positive plus a positive travels up up. 2) +1 + 4 = 5 3) -2 - 3 = -5 A negative plus a negative travels down down. Elevator Entrance 4) -3 - 4 = -7 -5 5) +2+6 = +8 -1 6) -5 -1 = -6

Both signs are the same so you end up traveling the same direction. 5 Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) +3 + 5 = 8 Both signs are the same so you end up traveling the same direction. 2) +1 + 4 = 5 3) -2 - 3 = -5 Elevator Entrance 4) -3 - 4 = -7 -5 5) +2+6 = +8 -1 6) -5 -1 = -6

Describe an easy way to add these integers? Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 Describe an easy way to add these integers? When the signs are the same and you are adding, just add the numbers and the sign stays the same. Elevator Entrance

Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 Watch the direction of the elevator when we do integer problems with the DIFFERENT SIGNS! Elevator Entrance

Adding Integers 2 1) -3 + 5 = +5 -3 Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 Elevator Entrance +5 -3

Adding Integers 2 -4 1) -3 + 5 = 2) -5 + 1 = -5 +1 Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 2) -5 + 1 = -4 Elevator Entrance -5 +1

Adding Integers 2 -4 -2 1) -3 + 5 = 2) -5 + 1 = 3) +2 + - 4 = +2 -4 Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 2) -5 + 1 = -4 3) +2 + - 4 = -2 +2 Elevator Entrance -4

Adding Integers 2 -4 -2 5 1) -3 + 5 = -3 2) -5 + 1 = +8 3) +2 - 4 = Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 -3 2) -5 + 1 = -4 +8 3) +2 - 4 = -2 4) +8 -3 = 5 Elevator Entrance

Adding Integers 2 -4 -2 5 1) -3 + 5 = 2) -5 + 1 = 3) +2 - 4 = -4 +4 Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 2) -5 + 1 = -4 3) +2 - 4 = -2 +4 -4 4) +8 -3 = 5 Elevator Entrance 5) +4 - 4 =

What do you notice about the direction of the integer elevator? Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 What do you notice about the direction of the integer elevator? 2) -5 + 1 = -4 3) +2 - 4 = -2 4) +8 - 3 = 5 Elevator Entrance 5) +4 - 4 = -6 6) -6 + 3 = -3 +3

A positive plus a negative travels up then down . 2 Adding Integers A positive plus a negative travels up then down . Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 2) -5 + 1 = -4 3) +2 - 4 = -2 4) +8 - 3 = 5 Elevator Entrance A negative plus a positive travels down then up. 5) +4 - 4 = -6 6) -6 + 3 = -3 +3

Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 1) -3 + 5 = 2 NOTICE: The integer elevator is moving in different directions because both numbers are different! 2) -5 + 1 = -4 3) +2 - 4 = -2 4) +8 - 3 = 5 Elevator Entrance 5) +4 - 4 = -6 6) -6 + 3 = -3 +3

Describe an easy way to add these integers? Adding Integers Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 Describe an easy way to add these integers? When the signs are the different and you are adding, just subtract the numbers and the larger number determines the sign. Elevator Entrance

SIGNS ARE THE DIFFERENT = TAKE THE DIFFERENCE! Adding Integers SIGNS ARE THE DIFFERENT = TAKE THE DIFFERENCE! Integer Elevator 8 7 6 5 4 3 2 1 -1 -2 -3 -4 -5 -6 -7 -8 When the signs are the different and you are adding, just subtract the numbers and the larger number determines the sign. Elevator Entrance

Try These 3 -5 = -4 + 7 = +3 - 4 = -6 + 7 = 5 -9 = -9 + 9 =