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.
450.
36
120 There are 6 digits in total. The numbers with 3 digits, with all digits distinct from each other, are the permutations of the 6 digits taken 3 at a time, and therefore there are 6*5*4 = 120 of them.
There are 167960 9 digits combinations between numbers 1 and 20.
10 digits are numbers in the billions.
there are 899 whole numbers that have three digits.
-99
99999
two
There are 5 numbers of 1 digit, 25 numbers of 2 digits, and 75 numbers of 3 digits. This makes 105 numbers in all.
how many numbers exactly have 4 digits ? 8900, 8999, 9000, 9999
17 digits
There are 5*4*3 = 60 such numbers.
With 123 digits you can make 123 one-digit numbers.
Numbers above 99 and under 1000 are 3-digits, all 900 of them.
there are nine digits in a tax id number