Let `A= {1,3,5,7,9}`.Insert the appropriate symbol `in or !in`in blank spaces:
2__A

Answer

To solve the problem, we need to determine whether the number 2 is an element of the set \( A = \{1, 3, 5, 7, 9\} \).

### Step-by-Step Solution:

1. **Identify the Set**: We are given the set \( A = \{1, 3, 5, 7, 9\} \). This set contains the elements 1, 3, 5, 7, and 9.

2. **Check for Membership**: We need to check if the number 2 is an element of the set \( A \). This means we need to see if 2 is listed among the elements of the set.

3. **List the Elements**: The elements of the set \( A \) are:
- 1
- 3
- 5
- 7
- 9

4. **Compare with the Number 2**: Now, we look for the number 2 in the list of elements:
- 1 (not 2)
- 3 (not 2)
- 5 (not 2)
- 7 (not 2)
- 9 (not 2)

5. **Conclusion**: Since the number 2 is not found in the set \( A \), we conclude that 2 does not belong to the set \( A \).

6. **Insert the Appropriate Symbol**: Therefore, we insert the symbol `!in` to indicate that 2 does not belong to the set \( A \).

### Final Answer:
The appropriate symbol to insert is:
\[ 2 \notin A \]