Q:

Two's Complement Value of 011101

I know the answer is 29 but I'm not sure how to arrive at it.
Usually I would take 011101 get its inverse of 100010 and add 1 to get
100011.
The value of this is 35. How then is the answer 29?

A:

011101 is 29  //Binary to Decimal
100011 + 011101 = 000000  //100011 is inverse+1
100011 = -011101  
100011 = -29

There is no '35' because in a two's compliment system any number starting with a '1' is a negative number.  This means, assuming 6 bits, that any number greater than 31 (011111) is in fact a negative number.  

