Please answer this alone very fastly
This is from congruence of numbers
Find the last two digits of 31997
3^1997
3*3^1996
3*(3^4)^499
3*(81)^499
Now we can do 81^499
Here unit place is 1 so 1st place will be 1
After we will multiply 8*9=72
But we can write only unit place because we need only last 2 digits
So the two digit is 21
But here 3 was in front of this factor.
So we have to multiply by 3
So the last two digit will be 3*21=63