the answer is = first 2-digit number by using 48= 28,82 and in 3 digit is=282,228,822,822
Number of 7 digit combinations out of the 10 one-digit numbers = 120.
There are twelve possible solutions using the rule you stated.
10,000 combinations.
There are 5,461,512 such combinations.
64
There is only 1 combination.
216
Using the eight digits, 1 - 8 ,-- There are 40,320 eight-digit permutations.-- There is 1 eight-digit combination.
There are 840 4-digit combinations without repeating any digit in the combinations.
There are 5,040 combinations.
There are 210 4 digit combinations and 5040 different 4 digit codes.
120 combinations using each digit once per combination. There are 625 combinations if you can repeat the digits.