Money — Class 3 Mathematics (Samacheer Kalvi)

TN State Board (Samacheer Kalvi) Class 3 Mathematics. Rupees and paise, bills and change.

1. Rupees and paise

Money is written with a dot between the rupees and the paise.

₹45.75 means 45 rupees and 75 paise. The part before the dot is rupees, the part after it is paise.

$₹1=100\text{paise}$

Paise always take two digits. Fifty paise is written ₹0.50, not ₹0.5. Five paise is written ₹0.05. Writing ₹0.5 is confusing, because it could be read as five paise when it means fifty.

2. Converting between rupees and paise

To turn rupees into paise, multiply by 100.

• ₹5 = 500 paise
• ₹3.50 = 350 paise
• ₹12.05 = 1205 paise

To turn paise into rupees, divide by 100.

• 475 paise = ₹4.75
• 250 paise = ₹2.50
• 1075 paise = ₹10.75

A quick check: the last two digits of the paise figure always become the paise part of the rupee figure.

3. Adding and subtracting money

Line the amounts up so that rupees sit under rupees and paise under paise, then work on each part.

₹35.50 + ₹12.75. Paise: 50 + 75 = 125. That is more than 100, so exchange 100 paise for ₹1: write 25 paise and carry ₹1. Rupees: 35 + 12 + 1 = 48. The answer is ₹48.25.

The commonest mistake is to ignore the dot and add all the digits together as one number. Adding ₹25.75 and ₹18.50 as 25 + 75 + 18 + 50 gives 168, which is not money at all. Rupees add to rupees and paise add to paise, exactly as metres add to metres.

4. Bills and change

A bill is the total of everything bought. Change is what comes back.

$\text{Change}=\text{Amount paid}-\text{Total bill}$

When paying with a ₹100 note, write it as ₹100.00 so the paise columns line up before subtracting.

5. Worked examples

Example 1. Convert ₹5.25 to paise, and 380 paise to rupees.

₹5.25 × 100 = 525 paise. 380 ÷ 100 = ₹3.80.

Example 2. Add ₹25.75 and ₹18.50.

Paise: 75 + 50 = 125, so write 25 and carry ₹1. Rupees: 25 + 18 + 1 = 44. The answer is ₹44.25.

Example 3. Ravi buys a pen for ₹18.50, a notebook for ₹35.75 and an eraser for ₹5.00. What is his bill?

Paise: 50 + 75 + 00 = 125, so write 25 and carry ₹1. Rupees: 18 + 35 + 5 + 1 = 59. The bill is ₹59.25.

Example 4. Ravi pays for that bill with a ₹100 note. What change does he get?

₹100.00 − ₹59.25. Paise: 00 − 25 will not go, so borrow ₹1 as 100 paise, giving 100 − 25 = 75. Rupees: 99 − 59 = 40. The change is ₹40.75.

6. Practice

1. Write forty rupees and five paise in rupee notation.
2. Convert ₹12.05 to paise.
3. Convert 2500 paise to rupees.
4. Add ₹22.60 and ₹17.55.
5. Subtract ₹28.40 from ₹50.00.
6. Meena buys rice for ₹42.50 and dal for ₹28.75. What is her total bill?
7. Meena pays with a ₹100 note. How much change does she receive?

7. Answers

1. ₹40.05, with two digits after the dot.
2. 1205 paise.
3. ₹25.00.
4. Paise 60 + 55 = 115, write 15 carry ₹1; rupees 22 + 17 + 1 = 40. Answer ₹40.15.
5. Paise 00 − 40 needs a borrow, giving 60; rupees 49 − 28 = 21. Answer ₹21.60.
6. Paise 50 + 75 = 125, write 25 carry ₹1; rupees 42 + 28 + 1 = 71. Answer ₹71.25.
7. ₹100.00 − ₹71.25 = ₹28.75.

8. Summary

• ₹45.75 is 45 rupees and 75 paise; the dot separates the two.
• ₹1 = 100 paise. Rupees to paise multiply by 100; paise to rupees divide by 100.
• Paise always take two digits: 50 paise is ₹0.50, never ₹0.5.
• Add rupees to rupees and paise to paise; never run the digits together.
• When the paise total passes 100, exchange 100 paise for ₹1 and carry it.
• Change = amount paid − total bill, and a ₹100 note is written ₹100.00 before subtracting.