Money — Class 4 Mathematics (Samacheer Kalvi)
TN State Board (Samacheer Kalvi) Class 4 Mathematics. Rupees and paise, profit and loss, and preparing a bill.
1. Rupees and paise
Indian money has two parts. The rupee is the big unit and the paisa is the small one.
1 rupee = 100 paise
We write an amount with a dot between the two: ₹45.75 means 45 rupees and 75 paise. The two digits after the dot are always paise, and there are always exactly two of them. So ₹8.50 is eight rupees and fifty paise — not eight rupees and five paise.
Converting. Rupees into paise, multiply by 100. Paise into rupees, divide by 100.
- ₹6 = 6 × 100 = 600 paise
- ₹4.25 = 425 paise
- 350 paise = 350 ÷ 100 = ₹3.50
2. Adding and subtracting money
Line up the dots, one under the other, and then add or subtract as usual. Keep the paise column two digits wide and carry a rupee whenever the paise reach 100.
₹45.75 + ₹23.50: the paise give 75 + 50 = 125, which is ₹1 and 25 paise. Carry the rupee: 45 + 23 + 1 = 69. The answer is ₹69.25.
3. Cost price and selling price
A shopkeeper does two things with every article. First she buys it, and the price she pays is the cost price (CP). Then she sells it, and the price she charges is the selling price (SP).
Compare the two and you can see how the shop is doing:
| Situation | What it means | How to find it |
|---|---|---|
| SP is more than CP | Profit | Profit = SP − CP |
| CP is more than SP | Loss | Loss = CP − SP |
| SP equals CP | Neither — this is called break even | — |
A shopkeeper buys a toy for ₹80 and sells it for ₹100.
Profit = SP − CP = 100 − 80 = ₹20
Now suppose she buys a shirt for ₹120 and has to sell it for ₹100.
Loss = CP − SP = 120 − 100 = ₹20
Notice that you always subtract the smaller amount from the bigger one. The order tells you which of the two names to use.
One thing you do not do this year. You are asked only for the profit or loss in rupees, never as a percentage. Percentage profit and loss come much later.
4. Preparing a bill
A bill lists what was bought, how much of it, and what it cost. For each line, multiply the quantity by the rate to get the amount. Then add the amounts to get the total.
| Item | Quantity | Rate | Amount |
|---|---|---|---|
| Notebook | 4 | ₹25 | ₹100 |
| Pen | 3 | ₹10 | ₹30 |
| Eraser | 2 | ₹5 | ₹10 |
| Total | ₹140 |
5. Working out the change
If you hand over more than the bill, the shopkeeper owes you the difference.
Change = amount paid − total
Paying the ₹140 bill above with a ₹200 note gives change of 200 − 140 = ₹60.
6. Worked examples
Example 1. Convert ₹7.40 into paise.
Solution: 7 × 100 = 700, plus 40 = 740 paise.
Example 2. A pen costs ₹50 and is sold for ₹65. Find the profit.
Solution: SP is more than CP, so it is a profit. Profit = 65 − 50 = ₹15.
Example 3. A bag costs ₹200 and is sold for ₹250. Profit or loss, and how much?
Solution: SP is more than CP, so it is a profit of ₹50.
Example 4. A cap is bought for ₹75 and sold for ₹75. What is the result?
Solution: CP and SP are equal, so there is neither profit nor loss. This is break even.
Example 5. Add ₹32.60 and ₹18.75.
Solution: The paise give 60 + 75 = 135, which is ₹1 and 35 paise. Carrying: 32 + 18 + 1 = 51. Answer ₹51.35.
Example 6. Amina buys 5 pencils at ₹8 each and pays with a ₹50 note. What change does she get?
Solution: Total = 5 × 8 = ₹40. Change = 50 − 40 = ₹10.
7. Practice
- How many paise make one rupee?
- Convert ₹9 into paise.
- Convert 275 paise into rupees.
- A book costs ₹120 and is sold for ₹100. Is this a profit or a loss, and of how much?
- Add ₹24.50 and ₹36.75.
- A shopkeeper buys a ball for ₹60 and sells it for ₹85. Find the profit.
- Prepare the total for 3 notebooks at ₹25 each and 2 pens at ₹15 each.
- Ravi pays a bill of ₹165 with a ₹200 note. How much change should he get?
8. Answers
- 100 paise.
- 9 × 100 = 900 paise.
- 275 ÷ 100 = ₹2.75.
- CP is more than SP, so it is a loss of 120 − 100 = ₹20.
- 50 + 75 = 125 paise, so carry ₹1: 24 + 36 + 1 = 61. Answer ₹61.25.
- 85 − 60 = ₹25 profit.
- 3 × 25 = ₹75 and 2 × 15 = ₹30, so the total is ₹105.
- 200 − 165 = ₹35.
9. Summary
- 1 rupee = 100 paise, and the two digits after the dot are always paise.
- Rupees into paise multiply by 100; paise into rupees divide by 100.
- Line up the dots when adding or subtracting money, carrying a rupee at 100 paise.
- Cost price is what the shopkeeper pays; selling price is what she charges.
- Profit = SP − CP when SP is bigger; Loss = CP − SP when CP is bigger; equal prices means break even.
- At this level, give profit and loss in rupees, never as a percentage.
- On a bill, amount = quantity × rate, and the total is the sum of the amounts.
- Change = amount paid − total.
