**Hundredth Part:** If you divide any thing into 100 equal parts, then each part would be known as hundredth part.

**Percentage:** By a certain percentage, we mean *“that many hundredth”*

We denote percentage by , thus

**Convert a Percentage into a Fraction**

For converting a percentage into fraction, divide it by and remove the sign.

Thus

Example:

**Convert Fraction into Percentage**

For converting a fraction into a percentage, multiply the fraction by and add sign to the resultant.

Example:

**Convert a Percentage into a Ratio**

A percentage can be expressed as a ratio with the first term equal to the given percentage and the second term equal to

Therefore,

Example:

**Convert Ratio into a Percentage**

First write the ratio as a fraction and then multiply the fraction by and put sign.

Therefore

Example:

** **

**Convert a Percentage into a Decimal**

First convert the percentage into fraction and then convert fraction into a decimal.

Example:

**Convert a Decimal into a Percentage**

First convert the given decimal into a fraction and then multiply the fraction by and add sign.

Example:

**Increasing or Decreasing a certain Quantity by a Certain Percentage**

- If you have to increase a number a by , then the new number would be

- If you have to decrease a number a by , then the new number would be