Form the greatest and smallest 5-digit number in each of the following by repeating any one of the digits. Also, use each digit in the number at least once.
`3, 4, 2, 6`

Answer

To solve the problem of forming the greatest and smallest 5-digit numbers using the digits 3, 4, 2, and 6, while repeating one digit and ensuring each digit is used at least once, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Digits**: The digits we have are 3, 4, 2, and 6.

2. **Form the Greatest 5-Digit Number**:
- To form the greatest number, we should use the largest digit available, which is 6.
- We will repeat the digit 6 to make a total of five digits.
- Arrange the digits in descending order: 6, 6, 4, 3, 2.
- Therefore, the greatest 5-digit number is **66432**.

3. **Form the Smallest 5-Digit Number**:
- To form the smallest number, we should use the smallest digit available, which is 2.
- We will repeat the digit 2 to make a total of five digits.
- Arrange the digits in ascending order: 2, 2, 3, 4, 6.
- Therefore, the smallest 5-digit number is **22346**.

### Final Answer:
- The greatest 5-digit number is **66432**.
- The smallest 5-digit number is **22346**.