Transcript Fractions, Decimals, and Percents

Fractions, Decimals, and Percents
Mr. Swaner
A Quick Review

Fractions, decimals, and percents are all
parts of a whole. They are also related and
can be converted back and forth.
0
1
4
1
2
3
4
1
0
.25
.50
.75
1
0%
25%
50%
75%
100%
Decimals

Decimals are like fractions because they also represent
parts of a whole, however, decimals use the base ten
system by place value. The place is named by the furthest
right number.
.01234
tenths, hundredths, thousandths, ten thousandths, hundred thousandths…….
0.1 is said “one tenth” because the furthest right number is in the tenth place.
0.17 is said “seventeen hundredths” for the same reason,
How would we say 0.83
“Eighty-three hundredths”
How would we say 0.015?
“fifteen thousandths,”
Converting decimals to fractions



Converting decimals to fractions is easy
because all we have to do is read the decimal
and it sounds the same as when we read the
fraction.
3
We read 0.3 as “three tenths.” which is 10
0.41 is read “forty-one hundredths.”
41
100

.07

.13

.3

.107
Fractions in base 10

Fractions in base 10 (denominator 10, 100,
1000……..) are easy because they are also
read the same way as decimals
3
10
7
100
Say it and Write it
9
10
15
100
Converting Fractions to Decimals



If the fraction has a denominator in base ten
(10, 100, 1,000 etc.) It works the same way.
7
100 is 0.07 both are read “seven hundredths.”
If the fraction does not have a base ten
denominator, you must use long division until
you get a repeating or terminating decimal.
Dividing out a Fraction
When dividing the fraction, it is important to make sure you have
the right number “in the house,” or inside the division symbol
3
5
house
basement
5 3
house
Dividing out a Fraction
When dividing the fraction, it is important to make sure you have
the right number “in the house.” or inside the division symbol
3
5
house
basement
5 3
5 3
house
3
5

0.6
Let’s Try a Few
Convert 0.49 to a fraction
49
100

Convert .083 to a fraction
83
1000

73
Convert 100 to a decimal
0.73



Convert
87
1000
3
Convert 8
to a decimal
0.087
to a decimal
8 3
Let’s Try a Few

Convert 0.49 to a fraction
49
100

Convert .083 to a fraction
83
1000

73
Convert
to a decimal
100
0.73

3
Convert
8
8 3
to a decimal

I wish I could do this sometimes during the
summer!
These are called terminating decimals

A terminating decimal ends
0.26
A Repeating Decimal

Ummmmmm it repeats. Use a bar to show it
repeats
0.33333333333333....  0.3
0.6767676767...  0.67
Day 2?
Warm Up

1) convert 0.16 to a fraction

3
2) convert
to a decimal
10

5
to a decimal
8
3) convert
Converting Numbers into Percents



When you have a fraction with a denominator in
base 10 (10, 100, 1,000), numbers can be
easily converted into percents.
The word percent literally means per hundred.
40 means you have 40 per hundred or 40%
100

7
How could we easily find what percent
is?
10
70
7 10

100
10 10
 70%
Converting Decimals to Percents






Lucky for us, decimals are ALL in base ten.
0.72 means 72 per hundred or 72%.
What happens if we have 0.851
How many hundredths are there? 85
The left over is just a decimal
85.1%
An easy rule for converting decimals to percents
is to simply move the decimal 2 places right.
Let’s Try Some
0.82  82%
0.258  25.8%
.012  1.2%
Percents to Decimals and Fractions

To convert a percent to a decimal, we do the
reverse. Instead of moving the decimal 2
places right, we move it 2 places left and
drop the % sign.
56%  56.0%  0.56
Try One on Your Own
Convert 27% into a decimal
27%  27.0%  0.27
Now convert 0.27 into a fraction
27
0.27 
100
Closure

How do you convert a decimal to a fraction?
Write it as it is read

How do you convert a fraction to a decimal?
Long divide

How do you convert a decimal to a percent?
Move the decimal right 2 places

How do you convert a percent to a decimal?
Move the decimal left 2 places