Transcript Converting Fractions to Decimals

Converting Fractions to Decimals
Adapted from free Powerpoints from the
website:
http://math.pppst.com/fractions.html
Discussion
Explain what a fraction is
• Explain what a decimal is
• Find a decimal that is equivalent
to ¼
• What method did you use to
find this?
•
Problem of the Day
Complete the following
Compare 5/13 to 4/9
Compare 0.384 to 0.4
Fraction is a comparison of two numbers
5/13 to 4/9
 To compare the size
of each part, the
“whole” must be cut
into the same size;
the denominators
must be the same

5 9
45
x 
13 9 117
4 13
52
x

9 13 117
Converting Fractions to Decimals

To convert a Fraction to a Decimal manually, follow
these steps:

Step 1: Find a number you can multiply by the bottom of
the fraction to make it 10, or 100, or 1000, or any 1
followed by 0s.

Step 2: Multiply both top and bottom by that number.

Step 3. Then write down just the top number, putting the
decimal place in the correct spot (one space from the right
for every zero in the bottom number)
Method #1: Converting with
Proportions
Example # 1: Express 3/4 as a Decimal
 Step 1: We can multiply 4 by 25 to become
100
 Step 2: Multiply top and bottom by 25

3 = 75
4
100
Example # 1 continued….
Step 3: Write down 75 with the decimal
place 2 spaces from the right (because
100 has 2 zeros);
 Answer = 0.75

Can you explain what we just did?
 Try to express ¼ as a decimal using
method # 1.

Method #2: Convert by Dividing

Example #1: to write 5/8 as a decimal, we
.6
need to calculate 5 ÷ 8:
8 5 .0 0
0.625
48
8 √ 5.000
20
So = 0.625 as a decimal.

Try this example: write 4/5 as a decimal using
division (method #2).
.80
5 4.00
40
0
Lets Practice!!
We are going to use this website to fish
out some fractions and decimals.
 Lets see how well you understand this
lesson.
 Go to www.iknowthat.com
 Select “Math” in the left margin
 Select “Fishy Fractions”
 Select “Fractions and Decimal Match”
