### A good answer might be:

>        00
>         10
>       + 01
>        ----
>         11

This is another case where the answer fits into the same number of bits as the numbers to add.

# Details, Details

Here are some details:

1. Usually the operands and the result have a fixed number of bits (usually 8, 16, 32, or 64). These are the sizes that processors use to represent integers.
2. If the bits in the leftmost columns of the sum are zero, include them in the answer to keep the result the same bit-length as the operands.
3. Compute the carry-out of the leftmost column, but don't write it as part of the answer (because there is no room.)
4. When the bit patterns are regarded as representing positive integers (unsigned binary representation), a carry-out of 1 from the leftmost column means the sum does not fit into the fixed number of bits. This is called Overflow.
5. When the bit patterns are regarded as representing positive and negative integers (as described in the last pages of this chapter), then a carry-out of 1 from the leftmost column is not necessarily overflow.

### QUESTION 5:

A particular processor chips (say the MIPS R2000) has registers of size 32 bits. How many bits does this processor typically use each time binary addition is performed?