INTEGERSINTEGERSINTEGERSINTEGERS

What is an Integer?

•An integer is a positive or negative whole number, including 0.

…-3, -2, -1, 0, 1, 2, 3…

There are “4”

Integer Operation

s

4 Integer Operations

• Addition +• Subtraction -• Multiplication x• Division ÷

Rule #1 for Adding Integers (+)

• The sum of two positive integers is always positive.

5 + 1 = 6

Rule #2 for Adding Integers (+)

• The sum of two negative integers is always negative.

-5 + (-1) = -6

Rule #3 for Adding Integers (+)

• The sum of a positive and a negative integer could be positive, negative, or zero.

Rule #3 for Adding Integers

Continued• When you add a positive and negative

integer, you are really subtracting. Then, you give the answer the sign of the greater absolute value.

5 + (-1) = -4

-5 + 1 = 4

-5 + (-5) = 0

Let’s Practice “Addition”

1) 5 + 6 =2) -3 + (-2) =3) -6 + 5 = 4) 8 + (-7) =5) -9 + 9 =

Let’s Check 1) 5 + 6 = 112) -3 + (-2) = -53) -6 + 5 = -14) 8 + (-7) = 15) -9 + 9 = 0

Rules for Subtracting Integers

(-)• To subtract an integer, add its

opposite.

• You will need to correctly change all subtraction problems into addition problems!

How do you change a

subtraction problem into an

addition problem?

There are three steps:

1. Keep the first integer the same. (Same)

2. Change the subtraction sign into an addition sign. (Change)

3. Take the opposite of the number

that immediately follows the newly placed addition sign. (Change)

Examples:

5 – (-2) = 5 + 2 = 7

-5 – 2 = -5 + (-2) = -7

Think …

Same, Change, Change

Let’s Practice “Subtraction”

1) 5 – 2 =2) -3 – 4 =3) -1 – (-2) =4) -5 – (-3) =5) 7 – (-6) =

Let’s Check 1) 5 – 2 = 5 + (-2) = 32) -3 – 4 = -3 + (-4) = -73) -1 – (-2) = -1 + 2 = 14) -5 – (-3) = -5 + 3 = -25) 7 – (-6) = 7+ 6 = 13

Rules for Multiplying Integers

(x)• The product of two integers with

the same signs is POSITIVE.

• The product of two integers with different signs is NEGATIVE.

Rules Summary for Multiplication

• Positive x Positive = Positive• Negative x Negative = Positive

• Positive x Negative= Negative• Negative x Positive = Negative

Let’s Practice “Multiplication”

1) 6 x (-3) = 2) 3 x 3 =3) -4 x 5 = 4) -6 x (-2) =5) -7 x (-8) =

Let’s Check

1) 6 x (-3) = -182) 3 x 3 = 93) -4 x 5 = -204) -6 x (-2) = 125) -7 x (-8) = 56

Did you know that the rules

for multiplication

and division are the same?

Guess what….

They are!

The rules for division are exactly the same as those for multiplication.

If we were to take the rules for multiplication and change the multiplication signs to division signs, we would have an accurate set of rules for division.

Rules for Dividing Integers (÷)• The quotient of two integers with

the same signs is POSITIVE.

• The quotient of two integers with different signs is NEGATIVE.

Rules Summary for Division

• Positive ÷ Positive = Positive• Negative ÷ Negative = Positive

• Positive ÷ Negative= Negative• Negative ÷ Positive = Negative

Let’s Practice “Division”

1) 18 ÷ (-2) = 2) -48 ÷ (-6) =3) -27 ÷ 9 = 4) 64 ÷ 8 =5) 30 ÷ (-5) =

Let’s Check

1) 18 ÷ (-2) = -92) -48 ÷ (-6) = 83) -27 ÷ 9 = -34) 64 ÷ 8 = 85) 30 ÷ (-5) = -6

Let’s Review…

What is an integer?

ANSWER•An integer is a positive or negative whole number, including 0.

Can you give an example of an

integer?

ANSWER•…-3, -2, -1, 0, 1, 2, 3…

What are the four operations?

ANSWER•The four operations are: addition, subtraction, multiplication, and division.

How do you add integers?

ANSWER• The sum of two positive integers is

always positive.• The sum of two negative integers is

always negative.• When you add a positive and negative

integer, you are really subtracting. Then, you give the answer the sign of the greater absolute value.

How do you subtract integers?

ANSWER• To subtract an integer, add its

opposite.• Same, Change, Change

How do you multiply integers?

ANSWER• If the signs are the same, your

answer is always positive.• If the signs are different, your

answer is always negative.

How do you divide integers?

ANSWER• If the signs are the same, your answer is

always positive.• If the signs are different, your answer is

always negative.

*Multiplication and Division Rules are the same!