What is the last digit of the number
4^2006
4^1= 4
4^2 = 16
4^3 = 64
4^4= 256
4^5 = 1024
You see a pattern?
4,6,4,6,4
every time the power is odd, it ends with 4
every time the power is even, it ends with 6
2006 is even, so the last digit is 6