If a number is formed by interchanging the digits at tens and thousands places of 7939, then which of the following is correct?

Options

A. New number `gt` Original number
B. New number` lt` Original number
C. New number = Original number
D. None of these

Answer

To solve the problem of interchanging the digits at the tens and thousands places of the number 7939, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Digits of the Number**:
The number given is 7939. We can break it down into its place values:
- Thousands place: 7
- Hundreds place: 9
- Tens place: 3
- Ones place: 9

2. **Identify the Places to Interchange**:
We need to interchange the digits at the tens and thousands places.
- Tens place digit is 3.
- Thousands place digit is 7.

3. **Interchange the Digits**:
After interchanging, the thousands place will now have the digit from the tens place (3), and the tens place will have the digit from the thousands place (7).
- New Thousands place: 3
- New Hundreds place: 9 (remains unchanged)
- New Tens place: 7
- New Ones place: 9 (remains unchanged)

4. **Form the New Number**:
Now, we can write down the new number using the new digits:
- New number = 3979

5. **Compare the Original and New Number**:
The original number is 7939, and the new number after the interchange is 3979.
- We can see that 7939 is greater than 3979.

### Conclusion:
Thus, the correct statement is that the original number (7939) is greater than the new number (3979).