27 if the digits can be repeated. 6 if not.
16.2 16 digit numbers and 2 digit decimal places.
There are 720 of them. The three digit counting numbers are 100-999. All multiples of 5 have their last digit as 0 or 5. There are 9 possible numbers {1-9} for the first digit, There are 10 possible numbers {0-9} for each of the first digits, There are 8 possible numbers {1-4, 6-9} for each of the first two digits, Making 9 x 10 x 8 = 720 possible 3 digit counting numbers not multiples of 5.
875
Not necessarily. Consider 444. The digits are not different. The first and second digits are not multiples of 3 The first digit is not greater than the second digit. In spite of all that, 444 is a 3-digit number
There are 7,290 different 4-digit numbers that can be formed from the digits 1-9 without repetition.
There are 60480 numbers.
-123456785
There are 504 such numbers.
-123456787
-123456786
A number divisible by 123456789 must be 0 or bigger than 123456789. It must, therefore have 1 digit or 9 digits (or more). A remainder of 1 makes no difference to the number of digits. In any case, there can be no number of 4 digits that is divisible by 123456789.
27 three digit numbers from the digits 3, 5, 7 including repetitions.
24
500
840
180 of them.