Money, Bills and Unit Price: Class 4 Study Guide
Shopping uses multiplication, division, addition and subtraction together. A unit price tells us the cost of one.
The unit price is the cost of one item or one kilogram or one litre. If 5 notebooks cost ₹150, one notebook costs 150 ÷ 5 = ₹30. If one notebook costs ₹30, 8 notebooks cost 30 × 8 = ₹240.
A bill lists each item, its quantity, its price and the total. Class 4 pupils read a bill carefully, check each line and find the change.
A bill to check
| Item | Quantity | Price each | Cost |
|---|---|---|---|
| Exercise book | 6 | ₹28 | ₹168 |
| Pen | 4 | ₹12 | ₹48 |
| Geometry box | 1 | ₹95 | ₹95 |
| Total | ₹311 |
Which is the better buy?
Compare prices by finding the cost of one. A 500 g pack of rice at ₹40 costs 40 ÷ 5 = ₹8 per 100 g. A 1 kg pack at ₹70 costs ₹7 per 100 g. The bigger pack is cheaper per 100 g. Always compare the same amount.
Divide the price by the amount.
100 g, 1 kg or 1 item.
That is cheaper.
Do not buy more than you use.
Rupees and paise in decimals
₹45.50 means 45 rupees and 50 paise. To add ₹45.50 and ₹12.75, line up the decimal points: 45.50 + 12.75 = ₹58.25. Subtract in the same way when finding change.
Worked examples and common mistakes
Example: 12 pencils cost ₹96. One pencil costs 96 ÷ 12 = ₹8. Example: You pay ₹500 for a ₹311 bill. Change = 500 − 311 = ₹189. Common mistakes: multiplying when the question asks for the cost of one, and not lining up decimal points. Read the question twice before choosing the operation.
Check your understanding: model answers
1. ₹12. 2. ₹140. 3. The 2 L bottle, at ₹30 per litre, against ₹32 per litre.
✨ Key Takeaways
- Unit price = total price ÷ number of items.
- Cost of many = unit price × quantity.
- Compare prices by the same unit.
- Line up decimal points to add or subtract money.
💬 Questions for Discussion & Reflection
- 6 pens cost ₹72. What does one pen cost?
- You buy 4 notebooks at ₹35 each. What is the total?
- A 2 L bottle costs ₹60 and a 1 L bottle costs ₹32. Which is cheaper per litre?
Print giving change worksheets (rupees) →