How many different 4-digit number can be formed with the digits 1,2,3,4 without any repetition ? Also find their sum.

Explanation

To solve the problem of finding how many different 4-digit numbers can be formed with the digits 1, 2, 3, and 4 without any repetition, and to find their sum, we can follow these steps:

### Step 1: Calculate the total number of 4-digit numbers
We have 4 digits: 1, 2, 3, and 4. Since we want to form a 4-digit number without any repetition, we can use the factorial concept.

- For the first digit, we can choose any of the 4 digits.
- For the second digit, we can choose from the remaining 3 digits.
- For the third digit, we can choose from the remaining 2 digits.
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