CLASS NOTES
CLASS : 8
SUBJECT : MATHEMATICS
CHAPTER :PERCENTAGE
Contents
PERCENTAGE
Meaning of Percentage
The word percent means per hundred or out of 100. It is represented by the symbol %.
45 12.5
45% = , 12.5% =
100 100
1
Hence, the symbol % stands for .
100
Percentage as a Fraction
A percentage can be expressed as a fraction with denominator 100.
x
x% =
100
Example:
68 17
68% = =
100 25
If the denominator of a fraction is not 100, we convert it into an equivalent fraction with
denominator 100.
Example:
3 3 × 12.5 37.5
= =
8 8 × 12.5 100
, 3
∴ = 37.5%
8
Important Formulae on Percentage
1. Conversion Between Percentage and Decimal
Percentage to Decimal: To convert a percentage into a decimal number, remove the % sign
and divide the number by 100.
x
x% =
100
Decimal to Percentage: To convert a decimal into a percentage, multiply the decimal by 100
and attach the % sign.
x = x × 100%
2. Finding Percentage of a Given Quantity
To find a certain percentage of a given quantity:
x
x% of a quantity = × quantity
100
3. Expressing One Quantity as a Percentage of Another
To express a quantity x as a percentage of another quantity y:
x
Percentage = × 100%
y
Note: Both quantities must be measured in the same units.
4. Finding the Original Quantity
If x% of a quantity is equal to y, then the original quantity is:
y × 100
Original Quantity =
x
CLASS : 8
SUBJECT : MATHEMATICS
CHAPTER :PERCENTAGE
Contents
PERCENTAGE
Meaning of Percentage
The word percent means per hundred or out of 100. It is represented by the symbol %.
45 12.5
45% = , 12.5% =
100 100
1
Hence, the symbol % stands for .
100
Percentage as a Fraction
A percentage can be expressed as a fraction with denominator 100.
x
x% =
100
Example:
68 17
68% = =
100 25
If the denominator of a fraction is not 100, we convert it into an equivalent fraction with
denominator 100.
Example:
3 3 × 12.5 37.5
= =
8 8 × 12.5 100
, 3
∴ = 37.5%
8
Important Formulae on Percentage
1. Conversion Between Percentage and Decimal
Percentage to Decimal: To convert a percentage into a decimal number, remove the % sign
and divide the number by 100.
x
x% =
100
Decimal to Percentage: To convert a decimal into a percentage, multiply the decimal by 100
and attach the % sign.
x = x × 100%
2. Finding Percentage of a Given Quantity
To find a certain percentage of a given quantity:
x
x% of a quantity = × quantity
100
3. Expressing One Quantity as a Percentage of Another
To express a quantity x as a percentage of another quantity y:
x
Percentage = × 100%
y
Note: Both quantities must be measured in the same units.
4. Finding the Original Quantity
If x% of a quantity is equal to y, then the original quantity is:
y × 100
Original Quantity =
x
