How many numbers lying between 100 and 1000 can be formed with the digits 0, 1, 2, 3, 4, 5, if the repetition of the digits is not allowed?

Explanation

To solve the problem of how many numbers lying between 100 and 1000 can be formed with the digits 0, 1, 2, 3, 4, and 5 without repetition of digits, we can follow these steps:

### Step 1: Determine the structure of the number
Since we are looking for three-digit numbers between 100 and 1000, the first digit (hundreds place) cannot be 0. Therefore, the valid choices for the first digit are 1, 2, 3, 4, or 5.

**Hint:** Remember that the first digit must be a non-zero digit to ensure it's a three-digit number.

### Step 2: Choose the first digit
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