copyright©amberpasillas2010. for learning to happen! take out a piece of paper. take out something...


For Learning to Happen!

•Take out a piece of paper.•Take out something to write with.•Try all of the examples.•Ignore all other distractions.•Watch the 1st slide then I will have you try a few examples.


1 • 1 = +1 1 • -1 = -1 -1 • -1 = +1

-1 • -1 • -1 = -1

Odd # of Negatives = Negative

Even # of Negatives = Positive

-1 • -1 • -1 • -1 = +1


1) 0.16x 30

00008+ 4084

12) 70

x 1.2041007048

+

3)

1

0.0048 x 32

690044635

1

1

1

2

0

0

1

+ 0

Try these on your paper!


Multiply (-3) (-0.14)

2

Step 1: Write the problem vertically 0.14

x 3Step 2: Ignore the decimal points and multiply Step 3: Determine where the decimal point goes in the product.

1

40

0.42

– . – = +

Step 4: Determine the sign of your answer using your integer rules.

The answer is POSITIVE


Multiply (-0.4) (0.6)

4

0.4

x 0.6

The decimal moves two places to the left

20

– 0. 24

Signs are the

sameSigns are

different

POSITIVE

NEGATIVE


Multiply (0.8) (-0.9)

2

0.8

x 0.9

The decimal moves two places to the left

70

– 0. 72

Signs are the

sameSigns are

different

POSITIVE

NEGATIVE


HOW MANY DECIMAL PLACES?

1 decimal place3.0

2) (-0.40)(-2.0)0.40 2.0

1) -3.0(0.20)

0.800

0.20 2 decimal places0.600 1 + 2 = 3 decimal

places

2 decimal place1 decimal places2 + 1 = 3 decimal places


3.0

2) (-0.40)(-2.0)0.40 2.0

1) -3.0(0.20)

0.800

0.200.600

WHAT IS THE SIGN OF YOUR ANSWER?

NEGATIVE

POSITIVE


Find the product.

(-2.8)(-3)

-2.8 -3

8.4 POSITIVE


Divide 0.27 -3

3 0 .27.0

0 02 7

9

27 0

Step 2: Move the decimal point in the dividend straight up into the quotientStep 3: Divide as usual.

Step 1: Write the problem in the long division format. Ignore the negatives.

TRICK: Dead Monkeys Smell Bad!

= -0.09

Step 4: Determine the sign.


Divide -0.65 5

5 0 .65.1

0 51 5

3

15 0

Step 2: Move the decimal point in the dividend straight up into the quotientStep 3: Divide as usual.

Step 1: Write the problem in the long division format. Ignore the negatives.

TRICK: Dead Monkeys Smell Bad!

= -0.13

Step 4: Determine the sign.


Multiply Negative DecimalsMultiply (-0.3) (0.9)

7

0.3

x 0.9

The decimal moves two places to the left.

20

– 0. 27

#10

Signs are the same

Signs are

different

POSITIVE

NEGATIVE


Divide Negative Decimals

Divide (- 0.75) (0.15)

015 0 75. 0

0 075

5

75 0

. .. .

#11

+ + = + – – = +

+ – = –– + = –

Signs are the same

Signs are different

POSITIVE

NEGATIVE

= – 5


Extras


0-2.0 -1.5 -1.0 -0.5 1.5 0.5

1.0 2.0

Negative Positive

-1

0.5

> -2

< 1.5

#

<Less than

>Greater than


+ + = +– – = +

+ – = –– + = –

Signs are the same

Signs are

different

POSITIVE

NEGATIVE

copyright©amberpasillas2010. for learning to happen! take out a piece of paper. take out something...

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