4-5 to 4-9 Review

Topic 4 Test Review Part 2

Review for Lessons 4-5 to 4-9

4-5: Use Models to Multiply a Decimal and a Decimal

• Remember, for one decimal factor you will shade columns

• For the other decimal factor, you will shade rows

Multiple Choice

Caden colored in the decimal grid shown. Which expression shows the area of the grid Caden colored?

• 0.04 x 0.05

• 0.04 x 0.5

• 0.4 x 0.5

• 0.4 x 0.05

4-6: Multiply Decimals Using Partial Products

• Rememnber, this basically means separating the numbers into whole number and decimal parts, and multiplying each part

Example: Multiply Decimals Using Partial Products

Separate Whole Numbers and Decimals and multiply using the Box Method. Then add each partial product.

Here is another example.

Multiple Select

What are the partial products of 5.8 x 1.3? Choose all partial products.

• 1 x 5 = 5

• 1 x 0.8 = 0.8

• 3 x 5 = 15

• 0.3 x 5 = 1.5

• 0.3 x 0.8 = 0.24

Fill in the Blanks

What is the actual product of 5.8 x 1.3? Add your partial products from the previous slide to find the total product.

4-7: Use Properties to Multiply Decimals

• You can turn decimals into fractions and regroup to multiply whole numbers x whole number and fractions x fractions, then convert the product back into a decimal

Take a look at this example.

Multiple Select

Choose all the expressions that are equal to 0.48 x 0.3

• $\frac{48}{100}\ \times\ \frac{3}{100}$

• $\frac{3}{10}\times\frac{48}{100}$

• $\frac{48}{100}\times\frac{30}{100}$

• $\frac{3}{100}\times\frac{48}{100}$

• $\frac{48}{100}\times\frac{3}{10}$

Multiple Select

Choose all the expressions that are equal to 0.8 x 0.07

• $\frac{8}{10}\times\frac{7}{100}$

• $\frac{80}{100}\times\frac{7}{10}$

• $\frac{8}{10}\times\frac{7}{10}$

• $\frac{7}{100}\times\frac{80}{100}$

• $\frac{7}{100}\times\frac{8}{100}$

Multiple Choice

What is the product of 0.702 x 10²?

• 7.02

• 7,020

• 70.2

• 0.702

Multiple Choice

What is the product of 7.02 x $10^3$  ?

• 7.02

• 7,020

• 70.2

• 0.702

Multiple Choice

What is the product of 702 x  $\frac{1}{10^3}$   ?

• 7.02

• 7,020

• 70.2

• 0.702

4-8: Use Number Sense to Multiply Decimals

• Estimate first

• Use your estimation to determine where the decimal point should be placed in the product

Fill in the Blanks

A small business plans to order carpet for 4 identical offices. The floor of each office is 7.2 feet long and 5.8 feet wide.

Round the length and width to the nearest whole number. Then estimate the total amount of carpet that is needed.

Multiple Choice

A small business plans to order carpet for 4 identical offices. The floor of each office is 7.2 feet long and 5.8 feet wide.

In the problem above - where should the decimal point be in the exact total area?

16704 square feet

• 1.6704 square feet

• 16.704 square feet

• 167.04 square feet

• 1,670.4 square feet

• 16,704 square feet

Multiple Choice

Without doing the multiplication, match the expression with the correct product. Use number sense.

6.32 x 0.15

• 26.52

• 0.948

• 21.456

• 38.512

Multiple Choice

Without doing the multiplication, match the expression with the correct product. Use number sense.

7.45 x 2.88

• 26.52

• 0.948

• 21.456

• 38.512

Multiple Choice

Without doing the multiplication, match the expression with the correct product. Use number sense.

8.16 x 3.25

• 26.52

• 0.948

• 21.456

• 38.512

Multiple Choice

Without doing the multiplication, match the expression with the correct product. Use number sense.

9.28 x 4.15

• 26.52

• 0.948

• 21.456

• 38.512

4-9: Multiply Decimals

• Multiplying decimals is similar to multiplying whole numbers

• Use the standard algorithm, and take out the decimals to multiply

• Then, add the decimal point back in to the product by counting the number of decimal places in the factors

Fill in the Blanks

Jonathan is shopping for a frame for a square painting. Each side measures 9.5 inches.

What is the perimeter of the painting?

Remember, P = l + l + w + w OR P = 2l x 2w

Fill in the Blanks

Jonathan is shopping for a frame for a square painting. Each side measures 9.5 inches.

What is the area of the painting?

Remember, A = l x w

Fill in the Blanks

A bowling alley charges

$185 per hour for parties. How much would a 2.5-hour party cost?

Fill in the Blanks

Every day, Isabella practices the piano for 0.75 hour and the flute for 1.4 hours. What is the total number of hours that she practiced in April? Reminder: April has 30 days.