9,999,876 is the greatest seven-digit number using four different digits.
greatest number9999987
98
98765.
987654
9876 and 1234
greatest number9999987
8642
98765.
9,876,543 is.
98
987654
That would be 99987.
99,999,876
99,999,987
999987
9876 and 1234
In order to make the number as big as possible, you would want the greatest value digits in the greatest place value. Thus the first number would have to be 9. Once 9 has been used, the second number would have to be 8. Then the third number would have to be 7 and so on. Therefore, the greatest 9 digit number with 9 different digits is 987,654,321.