The total number of natural numbers of six digits that can be made with digits , if all digits are to appear in the same number at least once, is
Formation of the number :
We need to find the number of natural numbers of six digits out of four digit, i.e. .
Thus, the digits are fixed and the other two digits could be same or different.
If both digits are same, then number of ways
If both digits are different then number of ways
Therefore, total number of ways
Hence option (A) is the correct option.