If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
Possible solutions - using your rules are:- 11,13,17,31,33,37,71,73 &77
64 if repetition is allowed.24 if repetition is not allowed.
15 of them.
125
If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
Possible solutions - using your rules are:- 11,13,17,31,33,37,71,73 &77
64 if repetition is allowed.24 if repetition is not allowed.
15 of them.
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
125
I take it that you want to make three digits numbers with 8,7,3, and 6 without repetition. The first digit cane be selected from among 4 digits, the second from 3 digits, the third digit from 2, hence the number of three digit numbers that can be formed without repetition is 4 x 3 x 2 = 24
Six (6)
There are 2000 such numbers.
9 odd numbers less than 100 can be formed. They are: 3,5,7,35,37,53,57,73 and 75.
There are 2000 such numbers.
9*8*7 = 504 of them.