9x8x7x6x5x4x3x2x1 or 9! which equals 362880 possible combinations if no digits are repeated
763920
500
It is 120 if the digits cannot be repeated.
5 digit telephone numbers having at least one of their digits repeated is = total possible 5 digit telephone numbers - 5 digit telephone numbers without any digit being repeated. =(10*10*10*10*10)-(10*9*8*7*6) =100000-30240 =69760
Interesting.Social Security numbers all have the form: (3 digits) - (2 digits) - (4 digits).That's 9 digits altogether. If you ignore the dashes, you get: xxx,xxx,xxx .With 9 places, there are 1 billion possible different numbers.
It is possible to create a 3-digit number, without repeated digits so the probability is 1.
6*5*4*3*2*1=720 possible numbers
There are 4 possible numbers if the digits are not repeated; 18 if they are. Those are 3-digit numbers, assuming that zero would not be a leading digit. If zero is allowed for a leading digit, then you can have 6 for the non repeated, and 27 if repetition.
If the digits may be repeated, and if the number may begin with a zero, then it's just all ofthe counting numbers up to 999,999,999.If it can't begin with a zero, then you have to throw away the first 99,999,999 and there canonly be 900,000,000.
98,764
Infinite. If numbers can be repeated, the list could go on nonstop.
0000-9999 (10x10x10x10 or 104) = 10,000 possible combinations allowing for repeated digits. If you are not able to repeat digits then it's 10 x 9 x 8 x 7 or 5,040 possible combinations without repeated digits.
763920
757
There are 5*4*3 = 60 such numbers.
24
500