1. Is this a positive or a negative number?
1011 is the binary representation of a negative integer, on 4 bits.
In a signed binary, the first bit (the leftmost) is reserved for the sign,
1 = negative, 0 = positive. This bit does not count when calculating the absolute value.
2. Construct the unsigned binary number.
Exclude the first bit (the leftmost), that is reserved for the sign:
1011 = 011
3. Map the unsigned binary number's digits versus the corresponding powers of 2 that their place value represent:
The number 1011(2) converted from a signed binary (base two) and written as an integer in decimal system (base ten):
1011(2) = -3(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.