Example 3 - Write numbers with given digits

The difference between the greatest 3 -digit number and the greatest 3 -digit number with distinct digits is

What is the smallest 3-digit number with unique digits?

Write all possible 3 -digit numbers using the digits 6,0,4, when repetition of digits is not allowed repetition of digits is allowed

Write all 3-digit numbers using the digits 1, 3, 5 taking each digit only once.

Write all 3 -digit numbers using the digit 2,3,5, taking each digit only once.

Write the greatest and the smallest 5-digit numbers, using the digits (digits may repeat): 1, 3 and 7

Write the greatest and the smallest 5-digit numbers, using the digits (digits may repeat): 3, 0, 5 and 7

Write all the possible 2-digt numbers using the digits 3, 4 and 5 without repeating any digit.

Write the greatest and the smallest 5-digit numbers, using the digits (digits may repeat): 2 and 6

Write the greatest and the smallest 5-digit numbers, using the digits (digits may repeat): 2, 6, 4 and 8