Think about the number of offsets that are possible. Since the physical address and the offset are sufficient to determine the segment, the number of possible logical addresses is equal to the number of possible offsets (except those offsets that yield an invalid segment number). Although it may appear that there are 65536 possible offsets, this is actually not the case because the segment returned by equation (3) must be an integer. For example, an offset of zero is not possible because equation (3) would return a segment of 179B 1/2 which is a non-integer. In addition, the segment must also be non-negative and less than 64K.