Transcript Decimals, Fractions, and Percents

Decimals, Fractions,
and
Percents
By
Lawren Brianna Ware
Definitions
• Decimal - Any number shown with a decimal
point; a number based upon tenths or
hundredths. ( 0.2, 0.375, 86.4 )
• Fraction - One or more of the equal parts of a
whole; a number usually expressed in the
form a/b. ( 1/3, 2 5/8, 7/4 )
• Percent- The word percent comes from Latin
and means “ for each hundred” or “ per
hundred.” ( 70%, 6.5%, 4.09% )
Converting Fractions to
Decimals
• To convert a fraction to a decimal, divide the
numerator by the denominator. Do this until you get
a decimal that terminates or repeats. If it repeats,
place a bar (--- ) over the first number that repeats.
Example 1: Convert 3/4 to a decimal
3/4 = 3÷4= 0.75
( terminating decimal)
Example 2: Convert 2/3 to a decimal
2/3= 2÷3= 0.66
( repeating decimal )
Converting Fractions to
Percents
• To convert a fraction to a percent, change the
fraction to a decimal ( by dividing the numerator by
the denominator ). Then multiply the decimal by 100
and put a percent sign (%). Another way is to move
the decimal point two places to the right and put a
percent sign (%).
Example 1: Convert 1/2 to a percent
1/2= 1÷ 2 = 0.50
0.50x 100= 50.00=50% or 0.50= 0. 5 0= 50%
Example 2: Convert 1/3 to a percent
1/3= 1÷3= 0.333
0.333x 100= 33.300=33.3% or 0.333=0. 3 3 3=33.3%
Converting Decimals to
Fractions
• In order to convert a decimal to a fraction, place the
number that follows the decimal point over the place
that it is in ( tenths, hundredths, thousandths, etc.).
Then simplify as necessary.
Example 1: Convert 0.7 to a fraction
0.7= 7/10 ( 7 is in the tenths place )
Example 2: Convert 0.25 to a fraction
0.25= 25/100= 1/4 ( 25 is in the hundredths place. 1/4 is
the simplified form of 25/100)
Example 3: Convert 1.625 to a fraction
1.625= 1 625/1000= 1 5/8 ( 625 is in the thousandths
place. 5/8 is the simplified form of 625/1000)
Converting Decimals to
Percents
• In order to convert a decimal to a percent,
either multiply the decimal by 100 and write
the percent sign (%), or move the decimal
point two places to the right and write the
percent sign (%).
Example 1: Convert 0.20 to a percent
0.20x 100= 20.00= 20% or 0.20= 0. 2 0= 20%
Example 2: Convert 4.00 to a percent
4.00= 4.00x 100= 400.00= 400% or 4.00= 4. 0
0=400%
Converting Percents to
Fractions
• When converting percents to fractions, change the
percent to a decimal ( divide the percent by 100 or
move the decimal point two places to the left ). Then
put the numbers behind the decimal point over the
place that it is in ( tenths, hundredths, thousandths,
etc.). Then simplify as necessary.
Example 1: Convert 85% to a fraction
85% = 85÷ 100= 0.85= 85/100= 17/20 ( 85 is in the
hundredths place. 17/20 is the simplified form of
85/100 )
Example 2: Convert 12.5% to a fraction
12.5%= 12.5÷ 100= 0.125= 125/1000=1/8 ( 125 is in the
thousandths place. 1/8 is the simplified form of
125/1000 )
Converting Percents to
Decimals
• When converting a percent to a decimal,
either divide the percent by 100 and put the
decimal point, or move the decimal point two
places to the left and put the decimal point.
Example 1: Convert 72% to a decimal
72%= 72÷ 100= 0.72 or 7 2 . 0= 0.72
Example 2: Convert 62.5% to a decimal
62.5%= 62.5÷ 100= 0.625 or 6 2 . 5= 0.625
Additional Explanations
dDwxNTM
0.78 or 78/100 or 78%
The grid above is divided into 100 equal parts. Of
these 100 parts, 78 have been shaded. If we were to
write this as a decimal, it would be 0.78; written as a
fraction, it would be 78/100; and written as a percent, it
would be 78%. All of these, 0.78, 78/100, and 78% are
equal. Each one represents 78 parts of the ( whole )
grid. Thus we are able to convert fraction to decimals,
decimals to percents, etc.
“Mathematics
is the door
and key to the
sciences.”
Roger Bacon