When you want to change decimal numbers to fractions, it is easier to think of them as fractions with a denominator of tenths, hundredths, and thousandths. Look at the fractions below, which show you the denominators of tenths, hundredths, and thousandths:
This is a fraction with a tenths denominator.
This is a fraction with a hundredths denominator.
And this is a fraction with a thousandths denominator.
Let's take a look at them with a number instead of boxes:
This number is five-tenths:
. When we write it as a decimal number, we write it this way: 0.5.
If you are writing five-hundredths,
, as a decimal number, you write it this way: 0.05.
If you want to convert a fraction with a denominator in the thousands, such as five-thousandths, or 
, you write it this way: 0.005.
Both 
and .005 tell about the same value, five-thousandths of one whole.
If we have a mixed number made up of a whole number and a fraction with a denominator of tenths, hundredths, or thousandths, we can write them as decimal numbers, too.
For example,
can be written as a decimal number: 7.3. You write the whole number first, then a decimal point, and then
as a decimal value.
Let's try another mixed number. How do you write
as a decimal number? The answer is 8.05.
What if the mixed number does not have a fraction with a tenths, hundredths, or thousandths denominator, like 
? First, we write the whole number 5 and then a decimal point. Then, to get the decimal value of the fraction 
we divide.
The decimal value of
is .5, so we write the mixed number 
as 5.5.
