Estimating the Difference by Rounding
To estimate the difference between 7436 and 3720 by rounding off to the nearest thousands, we will follow these steps:

Step 1: Round Each Number
- **7436**: When rounding to the nearest thousand, we look at the hundreds place (3). Since 3 is less than 5, we round down.
- Rounded value: **7000**
- **3720**: Similarly, we check the hundreds place (7). Since 7 is greater than or equal to 5, we round up.
- Rounded value: **4000**

Step 2: Calculate the Estimated Difference
- Now that we have rounded both numbers:
- 7000 (rounded from 7436)
- 4000 (rounded from 3720)
- The estimated difference can be calculated as:
- **7000 - 4000 = 3000**

Conclusion
- The estimated difference between 7436 and 3720, after rounding each number to the nearest thousand, is **3000**.
- This method simplifies calculations, making it easier to quickly assess the result without detailed arithmetic. Rounding is particularly useful in exams for swiftly processing numbers while maintaining reasonable accuracy.