Percent’s!
To convert a fraction to a percent, convert the fraction to a
decimal number and multiply it by 100% This moves the decimal point 2
spaces to the right! To convert a fraction to a decimal, divide top by
bottom.
3
to a percent.
5
0.6
3
 5 3.0 and 0.6  100%  60%
5
Convert
Convert
1
to a percent.
4
Answer:25%
NOTE:
Repeating decimals are a bit tricky.
1
Convert to a percent.
3
1
 3 1  0.3 When you multiply 0.3  100% , rewrite as
3
1
0.3333333...  100%  33.3333...%  33 %
3
To convert a percent to a decimal, remove the “%” sign and
multiply it by 0.01 (which means divide it by 100 or move the decimal point
2 spaces to the left).
Convert 34.6% to a decimal.
34.6%  34.6  0.01  0.346
Remember, for decimal multiplication, add the number of spaces behind the
decimal point of the numbers you are multiplying together – the answer has that
many spaces behind the decimal point.
Convert 7.5% to a decimal.
Answer:
.075%
To convert a decimal to a percent, multiply it by 100% (which
means move the decimal point 2 spaces to the right).
Convert 0.04 to a percent.
0.04  0.04  100%  4%
Convert 1.2 to a percent.
Answer:
120%
Solving Percent Problems With The Percent
Equation
Solving percent problems requires identifying the three elements of a basic
percent equation. These three elements are the percent, base and amount.
To translate a basic percent problem into the percent
equation
 translate "of" as a multiplication
 translate "is" as an equal sign
 write the percent as a decimal
 identify the “givens” and the unknown (base, amount, percent)
The basic percent equation is:
Percent of Base is Amount
Percent x Base = Amount
Finding the Amount:
What is 20% of 50?

The decimal equivalent of 20% is 20 x 0.01 = 0.20 = 0.2

Translate using the percent equation:
percent x base =
amount

Match the problem to the equation:
0.2
x
amount

Do the math:
amount
10
50
=
=

Write the answer:
10 is 20% of 50
What is 35% of 60?
Answer:21
Finding the Base:
35 is 5% of what number?
The decimal equivalent of 5% is 5 x 0.01 = 0.05
Translate using percent equation: percent
amount
Match the problem to the equation:
35
x
base =
0.05
x
base =
Do the math: divide both sides by 0.05.
1
0.05  base 0.05  base
On the left side of the "=",

 base
0.05
0.05
1
35
 0.05 35  5 3500  700
0.05
Putting the 2 sides together, base = 700
On the right side of the "=",
Write the answer:
35 is 5% of 700
45 is 30% of what number?
Answer:
150
Finding the Percent:
35 is what percent of 140?
Translate using percent equation: percent
amount
Match the problem to the equation:
35
x
percent
base =
x
140
=
Do the math: divide both sides by 140.
1
On the left side of the "=",
percent  140 percent  140

 percent
140
140
1
On the right side of the "=",
35
1
  0.25
140 4
Putting the 2 sides together, percent = 0.25
Convert from a decimal to a percent by multiplying by 100%: 0.25 x 100%
= 25%
Write the answer:
35 is 25% of 140
45 is what percent of 72?
Answer:
62.5%
Word Problems With Percent’s
If the original $10.80 price of an item is reduced by 10 percent,
what is the new price?
First we have to find the discount: 10% of the original price = discount.
This matches the percent formula:
percent of base
= amount.
The discount is calculated by 10% of 10.80 = 0.10 x 10.80 =$1.08
The new price is the original price minus the discount:
$10.80
 $1.08
$9.72
The new price is $9.72.
If the original $33.80 price of a radio is reduced by 30 percent, what
is the new price?
Answer:$23.66
A refrigerator is on sale for 25 percent off. If the sale price is $492, what
was the original price before the sale?
The sale price is 1 – 0.25 = 100% -25% = 75% of the original price.
percent
percent
0.75
x
x
x
base
original price
original price
=
=
=
amount
sale price
492
Dividing both sides by 0.75, we get
original price
The price before the sale was $656.
=
492
 75 49200  656
0.75
An air conditioner is on sale for 35 percent off. If the sale price is
$260, what is the original price before the sale?
Answer:
$400
15 games were won out of 25. What percent of the games were lost?
The number of games lost is 25 - 15 = 10
percent
percent
percent
x
x
x
base
total games
25
=
=
=
amount
games lost
10
Dividing both sides by 25, we get
percent
=
10 2
  5 2  0.4
25 5
Converting the decimal to a percent, 0.4 x 100% = 40%
40% of the games were lost.
24 books were read out of 48. What percent of the books
were read?
Answer:
50%