Subtraction is generally simpler than addition since only two numbers are involved and the upper value representation is greater than the lower value representation. The problem of "borrow" is similar in binary subtraction to that in decimal. We can contruct a subtraction table that has two parts  the three cases of subtracting without borrow, and the one case of the involvement of a borrow digit, no matter how far to the left is the next available binary digit.



 









 


and result = 1 

Last updated 2002/02/06
© J.A.N. Lee, 20002002.