12&8=(1000)2=______ & is used to AND two number bit wise?

Answer 1

I don't really understand your question, but the & operator is used for bitwise comparison of two numbers:

12 = 0b1100
08 = 0b1000
& - - - - - - - - -
= 0b1000

=> 12 & 8 = 8

Answer 2

12 = (1100)₂
8 = (1000)₂

1100
1000 &
_____
1000 = 8