**Unitary method** is the technique in algebra by using this method we can solve a problems involving quantity.

**Purpose of using this method:**

Suppose the price of an article is given. We can find the price of a number of articles.Int these kind of situation we need to use Method.In this method, we can find the value of one quantity from the given ones and then find the value of required number of quantities.

Here we have given three example problem to understand this topic better.

This topic is very useful for 5 and 6th grade students.

**Example 1:**

A trader buys 72 pens from a wholesale merchant at the price of $300 for 100 pens. How much does he pay for pens.

**Solution:**

Working rule:

From the given question we come to know that we have cost of 100 pens.The cost of 100 pens is $ 300.From this information first we need to find the cost of 1 pen,then we can find cost of required number of pens.

Price of 100 pens = $ 300

Price of 1 pen = 300/100

= $ 3

Price of 72 pens = 72 x Cost of 1 pen

= 72 x 3

= $ 216

**Example 2:**

The price of a dozen ball is $ 30. What is the price of 8 balls?

**Solution:**

1 Dozen = 12 items

Price of 12 balls = $ 30

Price of 1 ball = 30/12

= $ 2.5

Price of 8 balls = 8 x Cost of 1 ball

= 8 x 2.5

= $ 20

**Example 3:**

Cost of 5 books is $225.How many books can be bought for $810?

**Solution:**

Cost of 5 books = $ 225

Cost of 1 book = 225/5

= $ 45

Number of books for $810 = 810/Cost of 1 book

= 810/45

= 18

Number of books bought for $810 = 18