Math 9/7-9/10Math 9/7-9/10

9-7-10 9-7-10 Multiplying Multiplying

and Dividing and Dividing Decimals Decimals ReviewReview

Multiplying Decimals AnimationMultiplying Decimals Animation::

www.mathsisfun.com/.../decimals-multiplying-animation.html

Watch a teacher teach the lesson:Watch a teacher teach the lesson:

http://video.yahoo.com/watch/1434435?fr=yvmtf

Computation: You want to buy 5 packs of chicken at $1.99 each. How much will the total be? Estimate to the nearest dollar.

1. You want to buy 3 gallons of Edy’s Private Selection Icecream.How much will you spend? 2. You need 2 boxes of cereal. How much will you spend?

Dividing Dividing Decimals…Decimals…

These Goldfish boxes These Goldfish boxes are 2 FOR 6.99. How are 2 FOR 6.99. How much is much is eacheach box? box?

Each cucumber is 58 Each cucumber is 58 cents.cents.

You have spent You have spent $1.74 on cucumbers.$1.74 on cucumbers.

How many How many cucumbers did you cucumbers did you buy? buy?

You have been You have been taken to another taken to another

planet.planet.The head alien will not let you go home until you The head alien will not let you go home until you explain how to multiply and divide decimals.explain how to multiply and divide decimals.

Task:Task:Draw a step-by-step instruction manual on the Draw a step-by-step instruction manual on the following:following:

Multiplying decimalsMultiplying decimals

Dividing DecimalsDividing Decimals

Your manual must have:Your manual must have:An example of each type of problem An example of each type of problem

Each step should be labeled. Each step should be labeled.

Ticket out of the Ticket out of the door…door…

Read the problemRead the problem

Decide which strategy you will use.Decide which strategy you will use.

Solve the problem.Solve the problem.

Explain your answer.Explain your answer.

9/8/10 9/8/10 Modeling Multiplication Modeling Multiplication

of Decimalsof Decimalsdd

Shade in UP AND DOWN (green pencil)

.6 or 6/10

Shade in Side to Side (yellow pencil) .3 or 3/10

•Now, shade in:• .6 UP AND

DOWN with a green pencil.

•.3 SIDE TO SIDE with a yellow

pencil2. Count the

squares that are both green and

yellow.

1. What is the multiplication

problem?

What is the answer?

More Practice…More Practice…

.4X.8.4X.8

.5x.9.5x.9

.6x.4.6x.4

Another way to Another way to model…model…

Use flats, longs, Use flats, longs, and units…and units…

1.Place your 3.2 horizontally.1.Place your 3.2 horizontally.2. Place the 2.4 vertically2. Place the 2.4 vertically

2. Use your base ten blocks to fill in the remaining 2. Use your base ten blocks to fill in the remaining spaces.spaces.

3. The areas you have left will be filled with UNITS.3. The areas you have left will be filled with UNITS.

Ticket out of the Ticket out of the door…door…

Read the problemRead the problem

Decide which strategy you will use.Decide which strategy you will use.

Solve the problem.Solve the problem.

Explain your answer.Explain your answer.

9/9/109/9/10Working from the solution to the Working from the solution to the

problem…problem…

1. Use three hundreds grids OR draw three grids on a piece of graph paper. (10 by 10 array).

2. On grid #1: draw the decimal that is represented vertically (up and down).

3. On grid #2: draw the decimal that is represented horizontally (side by side).

4. On grid #3: draw both decimals and show the product of overlapping colors.

5. What is the problem? What is the product?

1. Use three hundreds grids OR draw three grids on a piece of graph paper. (10 by 10 array).

2. On grid #1: draw the decimal that is represented vertically (up and down).

3. On grid #2: draw the decimal that is represented horizontally (side by side).

4. On grid #3: draw both decimals and show the product of overlapping colors.

5. What is the problem? What is the product?

Practice, practice, Practice, practice, practice…..practice…..

Practice, practice, Practice, practice, practice…..practice…..

Create the following Create the following multiplication models:multiplication models:

.6x.8.6x.8

.7x.4.7x.4

.9x.2.9x.2

.6x.7.6x.7

Create the following Create the following multiplication models:multiplication models:

.6x.8.6x.8

.7x.4.7x.4

.9x.2.9x.2

.6x.7.6x.7

Steps:Steps:Draw the first decimal Draw the first decimal up and down. (Green up and down. (Green pencil)pencil)Draw the second Draw the second decimal side by side. decimal side by side. (Blue Pencil)(Blue Pencil)Draw both decimals Draw both decimals on the third grid with on the third grid with the same colors.the same colors.Count the colors that Count the colors that overlapped.overlapped.Write the problemWrite the problemWrite the productWrite the productCheck your work by Check your work by multiplying the multiplying the decimals.decimals.

Steps:Steps:Draw the first decimal Draw the first decimal up and down. (Green up and down. (Green pencil)pencil)Draw the second Draw the second decimal side by side. decimal side by side. (Blue Pencil)(Blue Pencil)Draw both decimals Draw both decimals on the third grid with on the third grid with the same colors.the same colors.Count the colors that Count the colors that overlapped.overlapped.Write the problemWrite the problemWrite the productWrite the productCheck your work by Check your work by multiplying the multiplying the decimals.decimals.

Visual Practice…Visual Practice…What would this multiplication problem and product be?

Review the Review the patterns.patterns.

Review the Review the patterns.patterns.

Ticket out of the Ticket out of the door…door…

Read the problemRead the problem

Decide which strategy you will use.Decide which strategy you will use.

Solve the problem.Solve the problem.

Explain your answer.Explain your answer.

9/10/10 Important 9/10/10 Important Vocabulary Vocabulary

How are you How are you doing?doing?

Ticket out of the Ticket out of the door…door…

Read the problemRead the problem

Decide which strategy you will use.Decide which strategy you will use.

Solve the problem.Solve the problem.

Explain your answer.Explain your answer.