Form the greatest and smallest -digit numbers using the digits only once.
Step 1: Write the greatest -digit number using the given digits
To find the greatest number formed by using any digits, we arrange them in descending order.
Therefore, the greatest 7-digit number formed using the digits
Step 2: Write the smallest -digit number using the given digits.
To find the greatest number formed by using any digits, we arrange them in ascending order.
Therefore, the smallest 7-digit number formed using the digits .
Hence, the required greatest and smallest numbers are and respectively.