Transcript DECIMALS

DECIMALS
ARE DELIGHTFUL!!!!
Adding and Subtracting
Decimals

What do you need to keep in
mind?

Line up decimal points
Contestant Pairs--You will be
shown three items-- Record
your price guess. All Items
were found on Walmart.com
April 6, 2011.
Magellan RoadMate 1700 7" Largescreen
Portable GPS with Spoken Street Names
Basic Math and Pre-Algebra for
Dummies (Paperback)
Better Homes and Gardens Autumn Lane 6-Piece
Dining Set, Black and Oak
Record your guess.
Magellan RoadMate 1700 7" Largescreen
Portable GPS with Spoken Street Names
The price:
$148.54
The price:
$18.90
Better Homes and Gardens Autumn
Lane 6-Piece Dining Set, Black and Oak
The Price:
$259.99
AND THE TOTAL IS:
1 2 1
148.54
18.90
+259.99
$427.43
Subtraction
Find the difference between your
total and the actual total.
Who came the closest without
going over?
And our winning contestant
pair is:
Multiplying Decimals
-Do not line up decimal points
-Start with the number with the
most digits and place the other
number underneath
-Multiply, not attending to the
decimal points
2.21 x .4 = 2.21
x .4
884
Multiplying Decimals
2.21 x .4
=
2.21
x .4
884
-Next, add the number of digits
after the decimal in each factor-Three
-Start at the right in your answer
and count to the left that many
places. That’s where you put
the decimal .884
Try a Few Yourself:
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.32 x .7
3.16 x 1.01
.018 x .26
0.224
3.1916
0.00468
Get ready to play the
Grocery Game
You will be shown 4 items, you
must determine the cost of each,
and you must decide how many
of each product you want to buy.
All items must be purchased.
Your total bill must be between
$19.00 & $20.00
Let’s view the items and play the
game:
Our winning contestant pair is:
Dividing Decimals

Place the first number “inside
the box,” the second number
outside
12.5 ÷ .3
.3 12.5
 **The key to remember is we
always need a whole number as
the divisor—the number outside
the box
 How do we change that number
to a whole number?
Dividing Decimals

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How do we change that number
to a whole number?
We multiply by a power of 10—
10,100,1000, etc.
The number of places we move
the decimal in the divisor to
make it whole is the same
number we must move in the
dividend
Dividing Decimals

Our new problem is now
.3. 12.3.
The decimal is placed in this new
position in the quotient.
41.
3. 123.
Dividing Decimals
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167.4 ÷ .93
9.447 ÷ 6.7
35.64 ÷ 33
180
1.41
1.08
Our next game is:
Easy as 1-2-3
Place the following items from the
current Walmart ad in order from
the lowest price to the highest
price:
Crisco Vegetable Oil—48 oz
Windex Glass Cleaner-32 fl.
oz.
33.8 oz. Aussie Shampoo or
Conditioner
Sally Hensen Diamond
Strength Nail Polish 0.45 oz
The correct order is:
Windex
Crisco
Nail Polish
Aussie
$ 2.97
$ 3.34
$ 3.98
$ 5.97
Our winning contestant pair is:
How much is each product per
ounce? Round to the tenthousandths place.
Windex 32 oz
$ 2.97
Crisco 48 oz
$ 3.34
Nail Polish .45 oz
$ 3.98
Aussie 33.8 oz
$ 5.97
.0928
.0696
8.844
.1766
To place numbers in order:
1. Line up decimals
 2. Add zeros as needed
 3. Remove decimal
Let’s try this one together:
6.25, 6.205, 6.2, 6.21
First, line up decimals
6.25
6.205
6.2
6.21

To place numbers in order:
Next, add zeros as needed:
6.250
6.205
6.200
6.210
Finally, remove decimal and put in order
from smallest to largest:
6250 4th
6205 2nd
6200 1st
6210 3rd
Your turn:
Place in order from smallest to
largest
8.09, 8.9, 8.909, 8.19
Let’s Practice Rounding
Decimals:
Divide and round to the nearest
hundredth:
 263.82 ÷ 4
Divide and round to the nearest
thousandth:
8.45 ÷ 0.69
Let’s Practice Order of
Operations with Decimals:
3.57 – (0.4)3 x 2.5 ÷ 5
19.36 ÷ (0.24 + 0.26) x (0.4)2
Thank you for playing
Decimals are Delightful!!!!
In-Class Problems:
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Pg. 166 Section 2.2 -- 12, 14,
15, 16. 19-22
Pg. 167 Section 2.3 -- 23-26
Section 2.4 -- 27-30, 33
Section 2.5 – 34-38
Pg. 168 Section 2.6 – 51-56