Kavita goes to a stationery shop near her school in Jaipur. She sees a sign: "5 pencils for Rs 30." She wants to buy 8 pencils. How much will she pay?
To solve this, we first find the cost of 1 pencil, and then multiply to find the cost of 8 pencils. This clever method is called the Unitary Method because we always find the value of one unit first.
What is the Unitary Method?
The unitary method is a way of solving problems where we first find the value of 1 unit (one item), and then use it to find the value of the number of units we need.
Step 1: Find the Value of 1 Unit
If we know the cost of several items, we divide to find the cost of 1 item.
Example: 5 pencils cost Rs 30. Cost of 1 pencil = Rs 30 / 5 = Rs 6.
Step 2: Find the Value of the Required Number of Units
Once we know the cost of 1 item, we multiply to find the cost of as many items as we need.
Cost of 8 pencils = Rs 6 x 8 = Rs 48.
The Two Steps -- Always Remember
| Step | What We Do | Operation |
|---|---|---|
| Step 1 | Find the value of 1 unit | Divide |
| Step 2 | Find the value of the required units | Multiply |
Writing the Solution Neatly
Always write your solution in this format:
Cost of 5 pencils = Rs 30
Cost of 1 pencil = Rs 30 / 5 = Rs 6
Cost of 8 pencils = Rs 6 x 8 = Rs 48
6 mangoes cost Rs 90. Find the cost of 10 mangoes.
Cost of 1 mango = Rs 90 / 6 = Rs 15
Cost of 10 mangoes = Rs 15 x 10 = Rs 150
3 notebooks cost Rs 45. Find the cost of 9 notebooks.
Cost of 1 notebook = Rs 45 / 3 = Rs 15
Cost of 9 notebooks = Rs 15 x 9 = Rs 135
A shopkeeper in Hyderabad sells 4 bangles for Rs 60. Sita wants to buy 7 bangles. How much will she pay?
Cost of 1 bangle = Rs 60 / 4 = Rs 15
Cost of 7 bangles = Rs 15 x 7 = Rs 105
| Word | Meaning |
|---|---|
| Unitary method | A method where we first find the value of 1 unit, then find the value of many |
| Unit | One single item or thing |
| Cost price | The amount of money needed to buy something |
| Divide | To split equally into parts |
| Multiply | To add a number to itself a certain number of times |
Market Visit: Ask a family member the price of any 3 items from a nearby shop. Write the details below and use the unitary method to find the cost of a different quantity.
| Item | Quantity Given | Total Cost (Rs) | Cost of 1 Item (Rs) | New Quantity | New Total Cost (Rs) |
|---|---|---|---|---|---|
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Kavita goes to a stationery shop near her school in Jaipur. She sees a sign: "5 pencils for Rs 30." She wants to buy 8 pencils. How much will she pay?
To solve this, we first find the cost of 1 pencil, and then multiply to find the cost of 8 pencils. This clever method is called the Unitary Method because we always find the value of one unit first.
What is the Unitary Method?
The unitary method is a way of solving problems where we first find the value of 1 unit (one item), and then use it to find the value of the number of units we need.
Step 1: Find the Value of 1 Unit
If we know the cost of several items, we divide to find the cost of 1 item.
Example: 5 pencils cost Rs 30. Cost of 1 pencil = Rs 30 / 5 = Rs 6.
Think about it: Why do we divide? Because we are splitting the total cost equally among all the items.
Step 2: Find the Value of the Required Number of Units
Once we know the cost of 1 item, we multiply to find the cost of as many items as we need.
Cost of 8 pencils = Rs 6 x 8 = Rs 48.
Think about it: Why do we multiply? Because if 1 item costs Rs 6, then 8 items will cost 8 times as much.
The Two Steps -- Always Remember
| Step | What We Do | Operation |
|---|---|---|
| Step 1 | Find the value of 1 unit | Divide |
| Step 2 | Find the value of the required units | Multiply |
Writing the Solution Neatly
Always write your solution in this format:
Cost of 5 pencils = Rs 30
Cost of 1 pencil = Rs 30 / 5 = Rs 6
Cost of 8 pencils = Rs 6 x 8 = Rs 48
Think about it: Rohan buys 4 notebooks for Rs 120. His sister wants 7 notebooks. Can you find the cost? What will you do first?
| Word | Meaning |
|---|---|
| Unitary method | A method where we first find the value of 1 unit, then find the value of many |
| Unit | One single item or thing |
| Cost price | The amount of money needed to buy something |
| Divide | To split equally into parts |
| Multiply | To add a number to itself a certain number of times |
6 mangoes cost Rs 90. Find the cost of 10 mangoes.
Cost of 1 mango = Rs 90 / 6 = Rs 15
Cost of 10 mangoes = Rs 15 x 10 = Rs 150
3 notebooks cost Rs 45. Find the cost of 9 notebooks.
Cost of 1 notebook = Rs 45 / 3 = Rs 15
Cost of 9 notebooks = Rs 15 x 9 = Rs 135
A shopkeeper in Hyderabad sells 4 bangles for Rs 60. Sita wants to buy 7 bangles. How much will she pay?
Cost of 1 bangle = Rs 60 / 4 = Rs 15
Cost of 7 bangles = Rs 15 x 7 = Rs 105
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Market Visit: Ask a family member the price of any 3 items from a nearby shop. Write the details below and use the unitary method to find the cost of a different quantity.
| Item | Quantity Given | Total Cost (Rs) | Cost of 1 Item (Rs) | New Quantity | New Total Cost (Rs) |
|---|---|---|---|---|---|