5th Grade Unit 5 (Multiplying & Dividing Decimals) Math Review

Powers of 10

1

2.6 x 10

26

2

0.05 x 10²

                            

5

3

6.258 x 100

625.8

4

0.2645 x 10³

264.5

5

4.5 x 10⁴

45,000

Multiplication

1

1.1 x 3

3.3

2

2.58 x 50

129.00

3

When multiplying decimals, the amount of numbers behind the decimal point is based on......

The numbers that are behind the decimal point of the numbers you are multiplying

4

Jackie earns $6.75 per hour babysitting. She works 5 hours on Friday and 4 hours on Saturday. How much did she make on those two days?

$6.75 x 9= $60.75

5

Joel takes his friends Ellie, Dina, Tommy, and Maria to the space museum. Each ticket costs $8.48 to get into the museum. If Joel pays for each ticket, including his own, how much does he spend in all?

$42.40

Division

1

8.4 ÷ 2

4.2

2

What is 127.2 divided by 24?

5.3

3

0.5 ÷ 11

0.045

4

Shyenne bought 4 yards of fabric for a total of $38.04. How much was the cost for one yard?

$9.51

5

Simon has $73.85. He wants to divide this amount evenly between himself and six of his friends. How much should each person get? 

$10.55

Estimation

1

What is the rule for rounding?

Five or more move it up,

Four or less let it rest!

2

What are compatible numbers for 14.5?

14 or 15

3

What does 453.5 round to?

454

4

Estimate this problem:

12.7 x 3

13 x 3=39

5

Estimate this problem:

133.2 ÷ 12

132 ÷ 12= 11

Important Reminders

1

The grouping of numbers does not change the product

Associative Property

2

What is it called when you are trying to find the closest number to a decimal?

Rounding

3

The answer to any number multiplied by one is equal to the number

Identity Property

4

What is it called when you have to find numbers that can be divided by the same number?

Compatible Numbers

5

The order in which numbers are multiplied does not change the answer

Communitive Property