Transcript h) Multiply Integers Day 1

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Multiplication - is repeated addition!
“Three times four” or
+ +
“Three groups of four”
=
4 + 4 + 4 = 3(4)= 12 square units
Multiplication  Repeated Addition
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TEACHER NOTE: I found this activity very
useful for students to help them with
understanding multiplication.
This lesson goes with the MULTIPLYING
INTERGERS WS INTERACTIVE. Make one copy of
the worksheet per student. Have them do the
problems with you as you model it in the
slideshow.
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You are going to get a handout (blue) called Multiply
Integers Study Guide.
You may use this as a study guide.
Take out something to write with.
Watch this slide show and follow along.
I will have you do problems on your handout that go with problems on
this slideshow.
Do not work ahead.
I do not want you making any mistakes.
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THE 1st NUMBER TELLS YOU:
HOW MANY GROUPS YOU HAVE
If the 1st number is positive you are adding
groups
If the 1st number is negative you are taking away groups.
If you take away something you need a zero bank.
THE 2nd NUMBER TELLS YOU:
HOW MANY NUMBERS ARE IN EACH GROUP
If the 2nd number is positive your numbers in each
group are positive.
If the 2nd number is negative your numbers in
each group are negative.
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Example a)
3(6) = Add 3 groups of positive 6
Example b)
-6(5) = Take away 6 groups of positive 5.
Example c)
-2(-6) = Take away 2 groups of negative 6.
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Write out what each multiplication problem means.
1) -5(2) = Take away 5 groups of +2.
You do NOT need to solve these!
2) 3(-2) = Add 3 groups of -2.
3) -5(-4) =Take away 5 groups of -4.
4) -8(1) = Take away 8 groups of +1.
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Write out what each multiplication problem means.
5) -2(-4) =Take away 2 groups of -4.
6) 11(3) = Add 11 groups of +3.
7) 7(-3) = Add 7 groups of -3.
8) -8(6) = Take away 8 groups of +6.
Turn your paper over!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
1) -3(2) = Take away 3 groups of +2
+
+
__
+
+
__
+_ +
_
= -6
Start with 6 zeros first!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
2) 5(-3) = Add 5 groups of -3
___
___
___
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= -15
___
___
Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
3) -2(-4) = Take away 2 groups of -4
++++
____
++++
____
= +8
Start with 8 zeros first!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
4) 1(-4) = Add 1 group of -4
____
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= -4
Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
5) -4(2) = Take away 4 groups of +2
+
+
__
+
+
+
+
__ __
+_ +
_
= -8
Start with 8 zeros first!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
Try # 6 & 7 on your own!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
6) -1(3) = Take away 1 group of +3
+_ +_ +
_
= -3
Start with 3 zeros first!
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Draw a picture to solve each problem. If you are taking
something away start with a zero bank. To show that you
take it away, circle it and attach an arrow to it. Write the
final value or answer.
7) -3(4) = Take away 3 groups of +4
+
+
+
+
____
+_ +_ +_ +_
+_+_+_+_
= -12
Start with 12 zeros first!
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After doing these problems, try to write you
own set of rules that describes how to multiply
INTEGERS without using a model. Look at the
examples on your paper to see a pattern.
8) A positive times a positive is a POSITIVE 2(6) = 12
9) A negative times a negative is a POSITIVE -2(-4) = 8
10)A negative times a positive is a NEGATIVE -1(3) = -3
11)A positive times a negative is a NEGATIVE 1(-4) = -4
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After doing these problems, try to write you
own set of rules that describes how to multiply
INTEGERS without using a model. Look at the
examples on your paper to see a pattern.
12) When the signs are the same and you multiply the answer is
POSITIVE
3(4) = +12 -3(-4)= +12
13) When the signs are the different & you multiply the answer is
NEGATIVE
-3(4) = -12 3(-4)= -12
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Signs are the same
Signs are different
Simplify.
1) 3  4  12



   
    POSITIVE
   NEGATIVE
  
4) 5(9)  45
2) 5  6   30
5) 3 6   18
3) 7(9)  63
6) 4(8)  32
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Aren’t integers
interesting?
TAKE OUT YOUR
STUDY GUIDE
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#12
MULTIPLY INTEGERS
Signs are the same
Signs are different



   
POSITIVE
   
Simplify.
1) 2  3  6
   NEGATIVE
  
4) 7( 8)  56
2) 4  8  32
5) 2  5  10
3) 6(4)  24
6) 3(10)  30
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