Assuming that leading zeros are not counted then:
The first digit can be one of {1, .. , 9} - a choice of 9.
For each of these the second can be one of the remaining 8 digits from {1, .., 9} plus the digit 0 - a choice of 9;
For each of these two choices, the third digit can be one of the 8 unchosen digits, etc.
Thus there are 9 × 9 × 8 × 7 × 6 = 27216 such numbers.
(10 x 9 x 8 x 7 x 6) = 30,240
There are 27216 such numbers.
9x9x8x7x6x5 = 81x56x30 = 136080
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
If the digits can be repeated, then there are (5 x 5 x 5 x 5) = 625 different four-digit numbers.If the digits can't be repeated, then there are (5 x 4 x 3 x 2) = 120 different four-digit numbers.
9
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
What is the sum of greatest 3-digit 4-digit 5digit
9x9x8x7x6x5 = 81x56x30 = 136080
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
There are 27 of them.
Any 3 out of 4 = 4. Each set can be arranged 6 ways so 24 different numbers.
If the digits can be repeated, then there are (5 x 5 x 5 x 5) = 625 different four-digit numbers.If the digits can't be repeated, then there are (5 x 4 x 3 x 2) = 120 different four-digit numbers.
It is possible to create a 3-digit number, without repeated digits so the probability is 1.
9
757
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
625 if numbers can have leading 0s, 500 otherwise.