Decimals

Decimals

The Decimal Point

ONE is the smallest whole number.

A decimal point is a small dot that always goes AFTER the ones place.

Numbers that come AFTER the decimal point are smaller than one. 

They are fractions or small parts of the number 1.

A decimal number can also be written as a fraction

A decimal number is the quotient of a decimal fraction.

A decimal fraction is a fraction whose denominator is 10-100- 10,000.........

examples 12/10,36/100

Multiple Select

Which numbers are less than 1?

• 1.2

• 0.7

• 0.093

• 2.2

Tenths

The first place after the decimal is the 10ths. 

0.1 is read as one tenth (1/10)

They are called 10ths because you need 10 tenths to make ONE.

10/10 = 1         0.1 x 10 = 1

Multiple Choice

273.41

What digit is in the 10ths place?

• 2

• 1

• 7

• 4

Hundredths

The next place is the 100ths place

0.01 is read as one hundredth (1/100)

100ths are smaller than 10ths, you need 100 of hundredths to make 1. 

100/100 = 1.      0.01 x 100 = 1

Multiple Choice

Which number is the biggest?

• 0.09

• 0.4

• 0.1

Thousandths

1000ths are smaller than 100ths or 10ths. 

0.001 is read as one thousandth (1/1000)

You need 1000 of thousandths to make 1 

0.001 x 1000 = 1

Open Ended

Write any number with an 8 in the thousandths (1000ths) place.

Multiple Choice

Decimal numbers can also be written as fractions. For example 0.8 can also be written as 8/10.

• True

• False

Multiple Choice

Which number is the biggest?

• 9.29

• 8.95

• 9.82

Converting Decimals to Fractions

Example:

0.1 = "One Tenth "

0.23 = "Twenty Three Hundredths "

1.75= "one and seventy-five hundredths "

Write what you read as a fraction

*When reading a decimal, make sure to use its official mathematical name!

*Write what you read as a fraction.

* Don't forget to simplify if possible!

 $\frac{7}{10}$  

look at the denominator we have 1 zero
there should be 1 digit after the decimal point

( so the decimal number is 0.7) 

 $\frac{8}{100}$  

look at the denominator we have 2 zeros 
there should be 2 digits after the decimal point

( so the decimal number is 0.08) 

Multiple Choice

What is 0.13 as a fraction?

• 1/3

• 3/1

• 13/100

Multiple Select

what is the decimal form of this number ? ( more than one possibility)

 $\frac{2,300}{10}$  

• 230.0

• 2.3

• 230

• 0.23

Multiple Select

 $\frac{12+8}{10}=?$  

• 2

• 0.12

• 0.8

• 2.0

let's practice together

3.79: three and seventy-nine hundredths

245.635:two hundred forty-five and six hundred thirty-five thousandths

11.2:eleven and two tenths