Last digit lesson 3

Contd. from the last post......
Case 2: If r=0 i.e. Power is divisible by 4.
Then write it as

A⁴

and get the answer.
Example:

3¹²³⁴⁸

Now 12348 is divisible by 4. So, the original expression reduces to

3⁴

i.e. 81 i.e. 1