DECIMALS DECIMALS

ARE DELIGHTFUL!!!!ARE DELIGHTFUL!!!!

Adding and Subtracting Adding and Subtracting DecimalsDecimals

What do you need to keep in What do you need to keep in mind?mind?

Line up decimal pointsLine up decimal points

Contestant Pairs--You will be Contestant Pairs--You will be shown three items-- Record shown three items-- Record your price guess. 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 Basic Math and Pre-Algebra for Dummies (Paperback) Dummies (Paperback)

Better Homes and Gardens Autumn Lane 6-Piece Dining Set, Black and Oak

Record your guess.Record your guess.

Magellan RoadMate 1700 7" Largescreen Portable GPS with Spoken Street Names

The price:

$148.54

The price:

$18.90

The Price:

$259.99

Better Homes and Gardens Autumn Lane 6-Piece Dining Set, Black and Oak

AND THE TOTAL IS:AND THE TOTAL IS:

11 22 11

148.54148.54

18.9018.90

++259.99259.99

$427.43$427.43

SubtractionSubtraction

Find the difference between your Find the difference between your total and the actual total.total and the actual total.

Who came the closest without Who came the closest without going over?going over?

And our winning contestant And our winning contestant pair is:pair is:

Multiplying DecimalsMultiplying Decimals

-Do not line up decimal points-Do not line up decimal points

-Start with the number with the -Start with the number with the most digits and place the other most digits and place the other number underneathnumber underneath

-Multiply, not attending to the -Multiply, not attending to the decimal pointsdecimal points

2.21 x .4 = 2.212.21 x .4 = 2.21

x .4x .4

884884

Multiplying DecimalsMultiplying Decimals

2.21 x .4 = 2.212.21 x .4 = 2.21 x .4x .4 884884-Next, add the number of digits -Next, add the number of digits

after the decimal in each factor--after the decimal in each factor--ThreeThree

-Start at the right in your answer -Start at the right in your answer and count to the left that many and count to the left that many places. That’s where you put places. That’s where you put the decimal .884the decimal .884

Try a Few Yourself:Try a Few Yourself:

.32 x .7.32 x .7 3.16 x 1.013.16 x 1.01 .018 x .26.018 x .26

0.2240.224 3.19163.1916 0.004680.00468

Get ready to play theGet ready to play theGrocery GameGrocery Game

You will be shown 4 items, you You will be shown 4 items, you must determine the cost of each, must determine the cost of each, and you must decide how many and you must decide how many of each product you want to buy. of each product you want to buy. All items must be purchased. All items must be purchased. Your total bill must be between Your total bill must be between $19.00 & $20.00$19.00 & $20.00Let’s view the items and play the Let’s view the items and play the game:game:

Our winning contestant pair is:Our winning contestant pair is:

Dividing DecimalsDividing Decimals Place the first number “inside Place the first number “inside

the box,” the second number the box,” the second number outsideoutside

12.5 12.5 ÷ .3 .3 12.5÷ .3 .3 12.5 **The key to remember is we **The key to remember is we

always need a whole number as always need a whole number as the divisor—the number outside the divisor—the number outside the boxthe box

How do we change that number How do we change that number to a whole number?to a whole number?

Dividing DecimalsDividing Decimals How do we change that number How do we change that number

to a whole number?to a whole number? We multiply by a power of 10—We multiply by a power of 10—

10,100,1000, etc.10,100,1000, etc. The number of places we move The number of places we move

the decimal in the divisor to the decimal in the divisor to make it whole is the same make it whole is the same number we must move in the number we must move in the dividenddividend

Dividing Decimals Dividing Decimals

Our new problem is nowOur new problem is now

.3.3.. 12.3 12.3..The decimalThe decimal is placed in this new is placed in this new

position in the quotient.position in the quotient.

41.33.. 123 123..

Dividing Decimals Dividing Decimals

167.4 ÷ .93167.4 ÷ .93 9.447 ÷ 6.79.447 ÷ 6.7 35.64 ÷ 3335.64 ÷ 33

180180 1.411.41 1.081.08

Our next game is:Our next game is:

Easy as 1-2-3Easy as 1-2-3

Place the following items from the Place the following items from the current current Walmart ad in order from in order from the lowest price to the highest the lowest price to the highest price: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:The correct order is:

Windex $ 2.97

Crisco $ 3.34

Nail Polish $ 3.98

Aussie $ 5.97

Our winning contestant pair is:Our winning contestant pair is:

How much is each product per How much is each product per ounce? Round to the ten-ounce? Round to the ten-thousandths place.thousandths place.Windex 32 oz $ 2.97

Crisco 48 oz $ 3.34

Nail Polish .45 oz $ 3.98

Aussie 33.8 oz $ 5.97

.0928.0928

.0696.0696

8.8448.844

.1766.1766

To place numbers in order:To place numbers in order: 1. Line up decimals1. Line up decimals 2. Add zeros as needed2. Add zeros as needed 3. Remove decimal3. Remove decimal

Let’s try this one together:Let’s try this one together:

6.25, 6.205, 6.2, 6.216.25, 6.205, 6.2, 6.21

First, line up decimalsFirst, line up decimals

6.256.25

6.2056.205

6.26.2

6.216.21

To place numbers in order:To place numbers in order:Next, add zeros as needed:Next, add zeros as needed:

6.2506.250

6.2056.205

6.2006.200

6.2106.210

Finally, remove decimal and put in order Finally, remove decimal and put in order from smallest to largest:from smallest to largest:

6250 6250 4th4th

6205 6205 2nd2nd

6200 6200 1st1st

6210 6210 3rd3rd

Your turn:Your turn:

Place in order from smallest to Place in order from smallest to largestlargest

8.09, 8.9, 8.909, 8.19 8.09, 8.9, 8.909, 8.19

Let’s Practice Rounding Let’s Practice Rounding Decimals:Decimals:

Divide and round to the nearest Divide and round to the nearest hundredth:hundredth:

263.82 ÷ 4263.82 ÷ 4

Divide and round to the nearest Divide and round to the nearest thousandth:thousandth:

8.45 ÷ 0.698.45 ÷ 0.69

Let’s Practice Order of Let’s Practice Order of Operations with Decimals:Operations with Decimals:

3.57 – (0.4)3.57 – (0.4)3 x 2.5 ÷ 5 x 2.5 ÷ 5

19.36 ÷ (0.24 + 0.26) x (0.4)19.36 ÷ (0.24 + 0.26) x (0.4)22

Thank you for playing Thank you for playing

Decimals are Delightful!!!! Decimals are Delightful!!!!

In-Class Problems:In-Class Problems:

Pg. 166 Section 2.2 -- 12, 14, Pg. 166 Section 2.2 -- 12, 14, 15, 16. 19-2215, 16. 19-22

Pg. 167 Section 2.3 -- 23-26Pg. 167 Section 2.3 -- 23-26 Section 2.4 -- 27-30, 33Section 2.4 -- 27-30, 33 Section 2.5 – 34-38Section 2.5 – 34-38 Pg. 168 Section 2.6 – 51-56Pg. 168 Section 2.6 – 51-56