The total number of three-digit numbers, with one digit repeated exactly two times, is ______________.

The number of 3-digit odd numbers, whose sum of digits is a multiple of 7, is _____________.

Let A be a 3 $$\times$$ 3 matrix having entries from the set {$$-$$1, 0, 1}. The number of all such matrices A having sum of all the entries equal to 5, is ___________.

The number of 7-digit numbers which are multiples of 11 and are formed using all the digits 1, 2, 3, 4, 5, 7 and 9 is _____________.