How many 6-digit telephone numbers  can be constructed with digits 0,1,2,3,4,5,6,7,8,9 if each number starts with 35 and no digit appears more than once?

Explanation

To solve the problem of how many 6-digit telephone numbers can be constructed starting with "35" and using the digits 0 to 9 without repetition, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Fixed Digits**: The first two digits of the telephone number are fixed as "35". Therefore, we only need to determine the last four digits.

2. **Available Digits**: The digits available for the last four positions are from the set {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}. However, since "3" and "5" are already used, the remaining available digits are {0, 1, 2, 4, 6, 7, 8, 9}. This gives us a total of 8 available digits.

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