Kristina has 4.5 pounds of taffy. She wants to share it evenly among

10 people. How much taffy will each person receive?

In this lesson you will learn how to divide decimal

numbers by powers of 10 by using what you know about

place value.

Let’s Review

30.0 6.0 0.1 0.02

+ 0.005

36.

Ones Period DecimalThousandths

Period

Hundreds

Tens Ones

Tenths

Hundredths

Thousandths

3 6 1 2 5 125

Let’s Review

15.6 ÷ 3 = 5.2

dividendquotient

divisor

Let’s Review

20.6 ÷ 10

(20 + 0.6) ÷ 10

2 0.06 2.06

+

=

(20 ÷ 10) (0.6 ÷ 10)

+

A Common Misunderstanding

Not thinking about the place value of the digits when dividing.

60.4 ÷ 100

(60 ÷ 100) + (4 ÷ 100)

(60 ÷ 100) + (0.4 ÷ 100) = 0.604

= 0.64

Let’s Review

101 =

102 =

103 =

104 =

105 =

1 x 1010

10 x 10100

10 x 10 x 101,000

10 x 10 x 10 x 1010,000

10 x 10 x 10 x 10 x 10100,000

The value of the exponent tells us how many times ten is multiplied by itself.

We can also say that the number of zeros in the product is equal to the value of the exponent.

Powers of 10

Core Lesson

= 1.0 = 0.1 = 0.01

Core Lesson

Ones Tenths Hundredths

1.3 ÷ 10

(1.0 ÷ 10) (0.3 ÷ 10)+

= 0.13

= 0.1 = 0.03

Core Lesson

Ones PeriodThousandths

Period

Hundreds

Tens Ones

Tenths

Hundredths

Thousandths

1.3 ÷ 11.3 ÷ 10

1.3 ÷ 100

1 . 3

Do you notice any patterns in the

dividends and the quotients?

Each time you divide a decimal by a power of 10, the digits in the quotient shift to the right.

.

.

1 . 3 1 3 1 . 3 1 3 0 1 3

Core Lesson

1.3 ÷ 1 = 1.3

1.3 ÷ 101

1.3 ÷ 102

But what is happening to the

location of the decimal point?

= 0.13

= 0.013

Each time you divide a decimal by a power of 10, the decimal point shifts to the left the same number of places as the value of the exponent.

1

2

Core Lesson

4.5 ÷ 10

This makes sense because 0.45 is 10 times smaller than

4.5

I can move the decimal point one place to the left in

4.5

4.5 = 0.45

In this lesson you have learned how to divide decimal numbers by powers of 10 by using what you know about place value.