Addition and Subtraction of Money
Adding and subtracting money works exactly like ordinary addition and subtraction of decimals, with one golden rule: keep the decimal points lined up so that rupees sit under rupees and paise under paise. When you add Rs 25.50 and Rs 13.75, you add the paise first (50 + 75 = 125 paise, which is 1 rupee and 25 paise), write down 25 paise, carry the 1 rupee, and then add the rupees (25 + 13 + 1 = 39), giving Rs 39.25. Subtraction follows the same alignment and uses borrowing when needed: to take Rs 17.80 away from Rs 50.00, you cannot subtract 80 paise from 00, so you borrow one rupee (100 paise) and work it through to get Rs 32.20. The most common mistake at this stage is treating the paise as if they were a separate whole number and forgetting that 100 paise roll over into 1 rupee, just as 100 centimetres roll over into a metre. A neat way to check any answer is to convert everything to paise, do the sum in whole numbers, and convert back. Real classroom practice uses shop role-play, where children total up purchases and then work out what is left from the money they brought.
✅ Solved examples
✏️ Practice — try these, take hints as needed
📝 Topic test — 8 questions
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Key Concepts — Quick Reference
Rupees and paise
| Basic equivalence | 1 rupee = 100 paise |
|---|---|
| Decimal form | Rs 45.75 means 45 rupees and 75 paise |
| Paise to rupees | 250 paise = Rs 2.50 |
| Rupees to paise | Rs 3.05 = 305 paise |
Cost, profit and change basics
| Total cost | Total = sum of (price x quantity) for each item |
|---|---|
| Profit | Profit = Selling Price - Cost Price (when SP is more) |
| Loss | Loss = Cost Price - Selling Price (when SP is less) |
| Change | Change = Amount Given - Total Cost |