Unitary Method

Unitary Method

By Fabian Chase

Unitary Method

​Let's look at the following example:

Fabian went to the toy store

and bought three tennis balls.                                   

These three tennis balls cost $12.

​

What would be the cost of 5 similar tennis balls?

​

​

Poll

Do you know the answer to the previous question?

• Of course I know the answer.

• I think so.

• Of course NOT!

Poll

Do you know about Unitary Method?

• I know a lot about Unitary Method.

• I know EVERYTHING about Unitary Method.

• I know a little bit about Unitary Method.

• I know nothing about Unitary Method.

To solve this problem we can use Unitary Method

What is unitary method?

We must first know what unitary method means.

​What is Unitary Method?

Unitary Method is the process of finding the value of (ONE) single unit and using that value of 1 unit, to help calculate the value of the required number of units.

Unitary Method| Mathematics

Definition of Unitary Method

​Unitary Method: Steps

There are 2 steps involved in solving a question using the Unitary Method.

Step 1: Find the cost of a unit.

Step 2: Use the cost of a unit to calculate the cost of other units.

Unitary Method| Mathematics

Steps of Unitary Method

Step 1: How to find the cost of a unit?

Remember that a unit can be:

One sock or

One potato or

One car or

One eyeball.

To find the cost of one unit we must:

         Divide the cost of multiple units by the number of units.

Unitary Method| Mathematics

How to find the cost of a unit?

​Unitary Method: Example #1

Four bananas cost $8.

What is the cost of 1 banana?

Unitary Method| Mathematics

Unitary Method: Example # 1

​Unitary Method: Example #1

Solution:

Divide the cost of the 4 bananas by the number of bananas.

Cost of 4 bananas = $12

Number of Bananas = 4

 

​

Unitary Method| Mathematics

Unitary Method: Example # 1 - Solution

​Unitary Method: Example #1

Solution:

Cost of 1 Banana = Cost of 4 bananas ÷ No. of Bananas

Cost of 1 Banana =              $8           ÷             4

Cost of 1 Banana = $2

 

​

​

Unitary Method| Mathematics

Unitary Method: Example # 1 - Solution

Multiple Choice

3 balls cost $12. What is the cost of 1 ball?

• $3

• $12

• $4

• $1

Multiple Choice

10 pencils cost $30. What is the cost of 1 pencil?

• $3

• $10

• $30

• $1

Multiple Choice

5 apples cost $25. What is the cost of 1 apple?

• $1

• $5

• $25

• $20

​Step 2: Calculate the cost of multiple units using the cost of one unit.

To find the cost of multiple units using the cost of 1 unit we must:

Multiply the cost of 1 unit by the number of desired units.

Unitary Method | Mathematics

Unitary Method: Step #2

Example:

The cost of 1 banana is $3.

What is the cost of 7 bananas?​

Solution:

Multiply the cost of 1 unit by the number of desired units.

Cost of 1 banana = $3

Number of desired bananas = 7   

Unitary Method | Mathematics

Unitary Method: Step #2

Example:

The cost of 1 banana is $3.

What is the cost of 7 bananas?​

Solution:

Cost of 7 bananas =     Cost of 1 unit    x     Number of desired units

Cost of 7 bananas =              $3             x            7

Cost of 7 bananas =               $21

Unitary Method | Mathematics

Unitary Method: Step #2

Multiple Choice

The cost of 1 car is $300.

What is the cost of 4 cars?

• $300

• $1

• $1200

• $400

Multiple Choice

The cost of 1 pizza is $12.

What is the cost of 8 pizzas?

• $300

• $1

• $1200

• $400

Multiple Choice

The cost of 1 soft drink is $2.50

What is the cost of 4 soft drinks?

• $10

• $2.50

• $4

• $1

​Unitary Method: Complete Example

Now that we understand both steps, let us try solving the first problem.

 

​

​

Unitary Method| Mathematics

Unitary Method: Complete Example

Fabian went to the toy store

and bought three tennis balls.                                   

These three tennis balls cost $12.

 

​

​

​Unitary Method: Solution

Unitary Method| Mathematics

Unitary Method: Complete Example - Solution

Step 1: Find the cost of 1 (ONE) ball.

Divide the cost of the 3 balls by the number of balls.

Cost of 3 balls    = $12

Number of balls = 3

Cost of 1 Ball =         Cost of 3 balls ÷    Number of Balls

Cost of 1 Ball =                 $12           ÷            3

Cost of 1 Ball =                             $4

​

​Unitary Method: Solution

Unitary Method| Mathematics

Unitary Method: Complete Example - Solution

Step 2:

Multiply the cost of 1 unit by the number of desired units.

Cost of 1 ball = $4

Number of desired balls = 5     

 

Cost of 5 balls =    Cost of 1 unit    X     Number of desired units

Cost of 5 balls =          $4               X            5

Cost of 5 balls =           $20

​

​Unitary Method: Solution

Unitary Method| Mathematics

Unitary Method: Complete Example - Solution

Step 2:

Multiply the cost of 1 unit by the number of desired units.

Cost of 1 ball = $4

Number of desired balls = 5     

Cost of 1 ball = $4

             Therefore the cost of 5 balls  =

               4 + 4 + 4 + 4 + 4 = 20                     

OR

                    4 x 5              = 20

​

Multiple Choice

3 balls cost $12. What is the cost of 5 balls?

• $3

• $12

• $4

• $20

Multiple Choice

10 pencils cost $30. What is the cost of 5 pencil?

• $15

• $10

• $3

• $30

Multiple Choice

5 apples cost $25. What is the cost of 20 apple?

• $20

• $5

• $85

• $100