Changing Fractions to Decimals
A PowerPoint for Ms Purcell’s 6th Grade
Answer the following question:
Fractions and Decimals are both
a. Whole Numbers
b. Odd Numbers
c. Rational Numbers
Answer to the Warm Up
• The answer is C – Fractions and Decimals
are both rational numbers.
• Fractions and decimals are different ways
of writing the same thing.
Changing Fractions to Decimals
Changing Decimals to Fractions
Decimals are fractions with a special set of
denominators—tenths, hundredths,
thousandths, etc.
You know these numbers as powers of 10.
Say the word name for the decimal out
loud as a fraction. e.g., say five-tenths.
Then write what you say. 5/10
Changing Decimals to Fractions
You try it:
 Say the decimal 0.64 as a fraction.
 If you said sixty-four hundredths you
were right!
 The word name for the decimal 0.64 is
the fraction sixty-four hundredths.
 Write: 64/100
Changing Decimals to Fractions
• Try these fractions on your own. Say the
decimal word name silently, then write what
you said as a fraction:





0.25
0.6
0.02
0.006
0.30
Changing Decimals to Fractions
Answers:
 25/100 or twenty five one-hundredths
 6/10 or six tenths
 2/100 or two one hundredths
 6/1000 or six one thousandths
 30/100 or thirty one hundredths
Changing Fractions to Decimals
How do we change a fraction to a decimal?
 Take a minute and talk about this with your
partner.
 Can you think of more than one way to solve
this problem?
Changing Fractions to Decimal
There are at least two ways to change a
fraction to a decimal:
1. If our fraction has a denominator that is
a power of ten, we can write the
fraction as the equivalent decimal. Or
2. We can divide the denominator into the
numerator--because a fraction is just a
way of showing division.
Changing Fractions to Decimals
If a fraction has a denominator that is a power
of ten, then changing the fraction to a decimal
is easy! Simply write the fraction as the
equivalent decimal. Like this:
25/100 = twenty-five one hundredths
The decimal equivalent is 0.25
Changing Fractions to Decimals
What if our fraction does not have a denominator
that is a power of 10?
If it’s not too much work, we can multiply the numerator
and denominator by another fraction that will change the
denominator to a power of 10.
Think: How can I change 3/25 to
something over 100?
Write: 3/25 x 4/4 = 12/100
Now write 12/100 as the decimal 0.12
Changing Fractions to Decimals
If it looks like too much work to change the
denominator, then simply divide the
denominator into the numerator like this:
Think: 2/8
Means two divided by eight
Write: 2 ÷ 8 = 0.25
Changing Fractions to Decimals
• Now you try it. Convert the following
fractions to decimals:
• 2/10
• 3/5
• 6/12
• 2/16
• 1/4
Changing Fractions to Decimals
•
•
•
•
•
•
Answers:
2/10 x 10/10 = 20/100 = 0.20
3/5 x 20/20 = 60/100 = 0.60
6/12 = 6 ÷ 12 = 0.5
2/16 = 2 ÷ 16 = 0.125
1/4 x 25/25 = 25/100 = 0.25
How did you decide which ones to change to a
power of 10 and which ones to divide?
Let’s play Jeopardy!
We will play in groups of four. You will need a
paper and pencil.
Your Assignment
• Create a list of four fractions with a
denominator of 10, 100, 1000 and 10,000 that
are equivalent to the same decimal
• Create a list of five fractions that will need to
be divided to change to decimals. Work the
problems and show your work.
• Draw a table with 100 squares that is equal to
16/80. Write this as a fraction and a percent.
Can you convert the denominator to