2. Multiply each bit by its corresponding power of 2 and add all the terms up.
11 1011 0011 1111(2) =
(1 × 213 + 1 × 212 + 1 × 211 + 0 × 210 + 1 × 29 + 1 × 28 + 0 × 27 + 0 × 26 + 1 × 25 + 1 × 24 + 1 × 23 + 1 × 22 + 1 × 21 + 1 × 20)(10) =
(8 192 + 4 096 + 2 048 + 0 + 512 + 256 + 0 + 0 + 32 + 16 + 8 + 4 + 2 + 1)(10) =
(8 192 + 4 096 + 2 048 + 512 + 256 + 32 + 16 + 8 + 4 + 2 + 1)(10) =
15 167(10)
The number 11 1011 0011 1111(2) converted from an unsigned binary (in base 2) and written as a positive integer (with no sign) in decimal system (in base ten):
11 1011 0011 1111(2) = 15 167(10)
Spaces were used to group digits: for binary, by 4, for decimal, by 3.