69375
It is a number with two digits in it. So it goes into the "tens" place of the numbers. Basically any whole number from 10 to 99. See how any number between those numbers only has 2 numbers, or digits that make up the number? 9 would only be a single-digit number, and 100 would be a triple-digit number.
There are only two smaller 3-digit numbers and both of them have repeated digits.
Any pair of digits (not including 0), can be used to generate 14 four-digit numbers. If one of the digits is 0, only seven will start with a non-zero digit.
There are only five distinct odd digits.
If the digits may be repeated, there are four choices for the first digit, four choices for the second, and four choices for the third. Thus there are 4x4x4 = 64 possible three-digit numbers with those digits. If the digits may not be repeated, there are still four choices for the first digit, but then only three remaining choices for the second, and then just two choices for the third. In this case there are only 4x3x2 = 24 possibilities.
There are 25 possibilities fitting those rules.
It is a number with two digits in it. So it goes into the "tens" place of the numbers. Basically any whole number from 10 to 99. See how any number between those numbers only has 2 numbers, or digits that make up the number? 9 would only be a single-digit number, and 100 would be a triple-digit number.
There are only two smaller 3-digit numbers and both of them have repeated digits.
Any pair of digits (not including 0), can be used to generate 14 four-digit numbers. If one of the digits is 0, only seven will start with a non-zero digit.
There are only five distinct odd digits.
500
If the digits may be repeated, there are four choices for the first digit, four choices for the second, and four choices for the third. Thus there are 4x4x4 = 64 possible three-digit numbers with those digits. If the digits may not be repeated, there are still four choices for the first digit, but then only three remaining choices for the second, and then just two choices for the third. In this case there are only 4x3x2 = 24 possibilities.
If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
Zero; all six digit numbers have six digits. Dude.. i m asking 6 digit numbers, containing only 4 different digits..!! e.g.:123412.. with only 2 digits repeated..!! My guess is: 10*9*8*7*4*3 but I'm also guessing that is wrong- sorry!
Only one . . . . . 18
625. Here's how:There are five odd digits {1,3,5,7,9} so our numbers will be made using only these digits. This is the same number of possibilities as if you had a base 5 number system where the allowed digits are {0,1,2,3,4}. For a 1 digit base-5, there are 5 possibilities, for a two digit base-5 there are 5² = 25 possibilities, so for a 4-digit, there are 5^4 = 625possible. This is the same number you will have with only using odd digits.
24 different numbers.