Difference in 1's and 2's Complement?

Answer 1

• 1's Complement, has two different codes for the number 0 (+0 & -0), negative numbers are the simple binary complement of positive numbers, is symmetrical (same number of negative and positive numbers can be represented), adder/subtractor must implement wraparound carry from MSB to LSB to get correct answer
• 2's Complement, has only one code for the number 0 (+0), negative numbers are 1 greater than the simple binary complement of positive numbers, is asymmetrical (one extra negative number than positive numbers), adder/subtractor is identical to a simple unsigned binary adder/subtractor without any special carry circuits needed