Note: These examples put the carry *underneath* the two subtrahends. The "Carry" flag is used as a "borrow" flag for subtraction. 0 1 0 1 0 1 1 0 1 0 0 0 1 1 0 1 first number - 0 0 1 1 0 0 0 1 1 1 0 0 1 1 1 0 second number (-borrow) 0 0 1 0 0 0 0 1 1 1 1 1 1 1 1 0 <== borrow _______________________________________ 0 0 1 0 0 1 0 0 1 0 1 1 1 1 1 1 ANSWER Zero:off Carry:off Sign:off Overflow:off (subtraction of two like-signed values is always valid in 2's Complement) ----- 1 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 first number - 0 1 1 1 0 0 0 0 1 1 0 0 0 1 1 1 second number (-borrow) 0 1 1 1 0 0 0 0 1 1 0 0 0 1 1 0 <== borrow ________________________________________ 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 0 ANSWER Zero:off Carry:off Sign:off Overflow:on (negative minus a positive is like adding two negatives and so the answer should be negative; if not, Overflow goes ON) Hit the "Back" button.