Write all possible 2-digit numbers that can be formed by using the digits 3, 7 and 9. Repetition of digits is allowed.

Write all possible numbers using the digits 3, 1 and 5. Repetition of digits is not allowed.

Write down the greatest number and the smallest number of 4 digits that can be formed by the digits 7, 5, 0 and 4 using each digit only once.

Rearrange the digits of the number 5701024 to get the largest number and the smallest number of 7 digits.