Step 1: To obtain the greatest number, put the greatest digit at the extreme left and then put the remaining digits in the descending order of their values with 0 at the end.
So, the greatest 6-digit number formed using the given digits is 765410.
Step 2: To obtain the smallest number, put the smallest digit (other than 0), then put 0, and then the remaining digits in the ascending order of their values.
So, the smallest 6-digit number formed using the given digits is 104567.