What is the decimal number for binary 101011?

Answer 1

in base 2 think of everything (right to left) in order of 2s...

2^0, 2^1, 2^2, 2^3, etc.

so if you have 101011, write those underneath (again, right to left).

now multiply the two top to bottom and add all of them:

so since you can get 2^5+2^3+2^1+2^0=32+8+2+1=43

good luck