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candrapetra
- Newbie | Next Rank: 10 Posts
- Posts: 5
- Joined: Sat Aug 20, 2011 4:28 pm
How many possible seven-digit phone number are there if no number begins with 0 or 555 ? if the number either has no 8 or no 9 ? If the number has no 8 and no 9 ?
is there anybody want to help me ?
is there anybody want to help me ?
