What is the last digit of `6^(100)` ?

Last digit of 5^100 is……

The last digit of 6^(50) is…………..

A three digit number n is such that the last two digits of it are equal and different from the first , the number of such n's is

What will be the units digit of the square of the following numbers :39.

What will be the units digit of the square of the following numbers :297.

What will be the units digit of the square of the following numbers : 5125.

What will be the units digit of the square of the following numbers :7286.