You have 9 options for the first position (all except zero); 9 options for the second position (any digit except the digit used for the first position; 8 options for the third position; 7 options for the fourth position; 6 options for the fifth position; and 5 options for the sixth position. Multiply everything together.
256
24
Without repeating digits (not digets!) and without leading 0s, 600 of them.
60
It is a repeating decimal.
256
24
Without repeating digits (not digets!) and without leading 0s, 600 of them.
98765
60
468, 486, 648, 684, 846, 864.
86420
It is a repeating decimal.
-58264
4 x 3 x 2 ie 24
5040
id say, 0123456789. but depends how many digits you can have