mu lit plying & dividing integers

8/14/2019 Mu Lit Plying & Dividing Integers

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MJ3MJ3

Ch 1.6 Multiplying & DividingCh 1.6 Multiplying & Dividing

IntegersIntegers


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BellworkBellwork

Answer the following:Answer the following:

2.2. What is the rule for adding integers ifWhat is the rule for adding integers if

the signs are the same?the signs are the same?3.3. What is the rule for adding integers ifWhat is the rule for adding integers if

the signs are different?the signs are different?

4.4. What is the rule for subtractingWhat is the rule for subtractingintegers?integers?

Reminder: To receive full credit you mustReminder: To receive full credit you mustwrite the question AND answer!write the question AND answer!


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Assignment ReviewAssignment Review

None there was no assignmentNone there was no assignment

yesterday.Woo hooyesterday.Woo hoo


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ObjectiveObjective

Students will multiply and divideStudents will multiply and divide

integersintegers


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Before we beginBefore we begin

Please take out your notebooks and getPlease take out your notebooks and get

ready to work.ready to work.

Todays lesson is relatively simple asTodays lesson is relatively simple as

the rules for multiplying and dividing arethe rules for multiplying and dividing are

the samethe same


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RulesRules

The rules for multiplying and dividingThe rules for multiplying and dividingintegers are the same:integers are the same:

If the signs are theIf the signs are the samesame the answer isthe answer ispositivepositive

If the signs areIf the signs are differentdifferent the answer isthe answer isnegativenegative

Here is what it looks like in symbolsHere is what it looks like in symbols


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SymbolsSymbols

Same Signs:Same Signs:

MultiplicationMultiplication

-- (-) = + (-) = +

+ + = ++ + = +

DivisionDivision

-- (-) = +(-) = +++ + = ++ = +

Different Signs:Different Signs:

MultiplicationMultiplication

-- + = - + = -

+ - = -+ - = -

DivisionDivision

-- + = -+ = -++ - = -- = -


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ProcessProcess I find that when multiplying or dividingI find that when multiplying or dividing

integers it is easier tointegers it is easier to

1. Evaluate the numbers first1. Evaluate the numbers first

2. Then evaluate the signs2. Then evaluate the signs This methodology allows you to focus on theThis methodology allows you to focus on the

each part of the problem by breaking it downeach part of the problem by breaking it downto smaller pieces and then putting all togetherto smaller pieces and then putting all together

increasing your chances of getting the correctincreasing your chances of getting the correctansweranswer

This is a real life strategy that can be used inThis is a real life strategy that can be used inyour everyday lifeyour everyday life


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Example #1Example #1

2(-5) =2(-5) =

2.2. Evaluate the numbers. In this case 2Evaluate the numbers. In this case 2

time 5 = 10time 5 = 10

3.3. Evaluate the signs. In this caseEvaluate the signs. In this case

positive times a negative is negativepositive times a negative is negative

2(-5) = -102(-5) = -10


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Example # 2Example # 2

-8(-4) =-8(-4) =

2.2. Evaluate the numbers first. In thisEvaluate the numbers first. In this

case 8 times 4 = 32case 8 times 4 = 32

3.3. Evaluate the signs. In this caseEvaluate the signs. In this case

negative times a negative = a positivenegative times a negative = a positive

-8(-4) = +32-8(-4) = +32


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Your TurnYour Turn

In the notes section of your notebookIn the notes section of your notebook

write and complete the following:write and complete the following:

6(-8) =6(-8) =

-2(4) =-2(4) =

-3(-7) =-3(-7) =

(-5)(-5)22


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Multiplying More Than 2 IntegersMultiplying More Than 2 Integers

When multiplying more than 2 integersWhen multiplying more than 2 integersuse the order of operations. That isuse the order of operations. That is

multiply in order from left to right.multiply in order from left to right. Again, use the process whereby youAgain, use the process whereby you

evaluate the numbers first, thenevaluate the numbers first, thenevaluate the signsevaluate the signs

Here is what it looks likeHere is what it looks like


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ExampleExample

-2(3)(-9) =-2(3)(-9) =

2.2. Multiply 2 times 3 to get 6.Multiply 2 times 3 to get 6.

3.3. Negative times positive is negative toNegative times positive is negative to

getget -6(-9) =-6(-9) =

4.4. Multiply 6 times 9 to get 54Multiply 6 times 9 to get 54

5.5. Negative times a negative is positiveNegative times a negative is positive

-2(3)(-9) = 54-2(3)(-9) = 54


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Your TurnYour Turn


write and complete the following:write and complete the following:

-4(-8)(-5) =-4(-8)(-5) =

-2(-4)-2(-4)22


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DivisionDivision

Since the rules for multiplication andSince the rules for multiplication and

division are the same use the samedivision are the same use the same

process.process.

2.2. Evaluate the numbersEvaluate the numbers

3.3. Evaluate the signsEvaluate the signs

Here is what it looks likeHere is what it looks like


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ExampleExample

-24-24 3 =3 =


divide by 3 = 8divide by 3 = 8

3.3. Evaluate the signs. In this case aEvaluate the signs. In this case a

negative divided by a positive = anegative divided by a positive = a

negativenegative

-24-24 3 = -83 = -8


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ExampleExample

-25-25 (-5) =(-5) =


divided by 5 is 5divided by 5 is 5

3.3. Evaluate the signs. In this case aEvaluate the signs. In this case a

negative divided by a negative is anegative divided by a negative is a

positivepositive

-25-25 (-5) = +5(-5) = +5


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Your TurnYour Turn

In the notes section of your notebook writeIn the notes section of your notebook write

and complete the following:and complete the following:

-28-28 (-7)(-7)

3636

-2-26.6. -40-40

88


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SummarySummary


summarize the key concepts covered insummarize the key concepts covered in

todays lessontodays lesson We discussedWe discussed

The rules for multiplication and divisionThe rules for multiplication and division

When the signs are the sameWhen the signs are the same When the signs are differentWhen the signs are different


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AssignmentAssignment

Text p. 617 Lesson 1.6 # 1 30Text p. 617 Lesson 1.6 # 1 30

ReminderReminder

II do notdo not accept late assignmentsaccept late assignments

II do notdo not accept answers only for anyaccept answers only for any

assignment.assignment.

You must write the problem & show howYou must write the problem & show howyou got your answeryou got your answer

mu lit plying & dividing integers

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