Money & Time – ICSE Mathematics
(Class 1 – 10)
Why this topic matters
Money and time are everyday concepts that help you solve real‑world problems – from buying a toy to calculating how long a trip will take. Mastering them builds confidence in arithmetic, fractions, decimals and logical thinking.
Table of Contents
- Class 1–2: The Basics
- Class 3–4: Coin‑Note & Clock Basics
- Class 5–6: Decimals, Percentages & Simple Time Calculations
- Class 7–8: Ratios, Interest & Advanced Clock Work
- Class 9–10: Compound Interest, Currency Conversion & Time‑Distance
- Quick Revision Summary
1. Class 1–2: The Basics
Simple Explanation
- Money: Coins (e.g., ₹0.5, ₹1) and notes (₹10, ₹20).
- Time: Hours and minutes on a clock.
Key Points
| Concept | What to Look For | How to Solve |
|---|---|---|
| Adding coins | Count the total number of coins | Add the values (e.g., 3 ₹1 + 2 ₹0.5 = ₹5) |
| Subtracting money | Find how much is left after a purchase | Subtract the price from the amount paid |
| Reading a clock | Identify the hour (long hand) & minute (short hand) | 3 o’clock = 3:00; 6 o’clock = 6:00 |
| Simple time addition | Add minutes to a given time | 3:10 + 20 min = 3:30 |
Worked Example
Problem: A child has five ₹1 coins and four ₹0.5 coins. She buys a book costing ₹4.
Solution
- Total money:
(5 \times 1 + 4 \times 0.5 = 5 + 2 = ₹7) - Change:
(₹7 - ₹4 = ₹3).
Revision Summary
- Coins add by value, not by count.
- Use the long hand for hours, short hand for minutes.
- Adding minutes can cross an hour (e.g., 12:50 + 15 min = 1:05).
2. Class 3–4: Coin‑Note & Clock Basics
Simple Explanation
- Money: Combine coins and notes; understand values like ₹5, ₹10, ₹20.
- Time: Read minutes and hours; compute simple intervals.
Key Points
| Money | Time |
|---|---|
| Mixed addition | Clock reading |
| Add notes and coins together (e.g., ₹10 + 3 ₹1 + 2 ₹0.5 = ₹13.5). | Identify hour and minute from the positions. |
| Money subtraction | Subtracting time |
| Subtract the cost from the amount (e.g., ₹25 – ₹13.5 = ₹11.5). | Subtract minutes or hours, borrow if needed. |
Worked Example
Problem:
- A student has ₹50, ₹10, and ten ₹1 coins.
- He buys a pen for ₹18.30.
- A clock shows 4 : 20. He spends 55 minutes on a test. What time does he finish?
Solution
- Total money:
(₹50 + ₹10 + 10\times1 = ₹70). - Change after the purchase:
(₹70 - ₹18.30 = ₹51.70). - Test finish time:
(4:20 + 55,\text{min} = 5:15).
Revision Summary
- Keep coin and note values in the same unit (₹).
- When adding minutes, if the sum ≥ 60, increase the hour by 1 and subtract 60 from minutes.
- Always double‑check the final time by visualising on a clock.
3. Class 5–6: Decimals, Percentages & Simple Time Calculations
Simple Explanation
- Money: Work with decimals, find percentages (e.g., discounts).
- Time: Convert between hours, minutes, seconds; compute differences and average speeds.
Key Points – Money
| Concept | Formula / Method | Example |
|---|---|---|
| Discount | ( |