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.
5
8,ooo
0 and 5. Every multiple of 5 ends in one of those 2 digits. 5 times any even number ends in 0; 5 times an odd number ends in 5.
The natural numbers, in normal usage, have only 9 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.The natural numbers, in normal usage, have only 9 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.The natural numbers, in normal usage, have only 9 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.The natural numbers, in normal usage, have only 9 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
99999
There are 90000 5-digit numbers.
There are 5*4*3 = 60 such numbers.
10001
All of them.
90000 of them.
one
500
There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.
There are 5460 five digit numbers with a digit sum of 22.
Assuming that the first digit can't be zero: If repetition of digits is permitted: (5 x 6 x 6) = 180 numbers of 3 digits. If repetition of digits is not permitted: (5 x 5 x 4) = 100 numbers of 3 digits.
If you're limited to only 5 digits that can't be repeated, then there are 120 ways they can be arranged.