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Binary Addition

                 Binary addition is similar to the addition of decimal numbers. In Binary Number System, when
                 the value of addition exceeds the value 1, say 10 or 11, then 1 is carried over to the left of the

                 current position. The rules for adding two binary digits are given below:

                                              X               Y                  X + Y

                                              0               0                0 + 0 = 0

                                              0               1                0 + 1 = 1
                                              1               0                1 + 0 = 1


                                              1               1           1 + 1 = 10 (carry 1)

                 For example, let us add the binary numbers (101111)  and (10111) .
                                                                                   2
                                                                      2
                                                                       _____
                                                    1    1  1  1  1          Carry bits
                                                    1    0  1  1  1  1
                                                +        1  0  1  1  1

                                                1  0     0  0  1  1  0

                 Binary Subtraction

                 In binary subtraction, binary number of lower value is subtracted from the binary number of
                 higher value. The following table explains the subtraction of digit Y from digit X. If Y is greater

                 than X, then 1 is borrowed from the next position. When the binary digit 0 borrows 1 from the
                 next most significant digit, it becomes 10.

                                         X        Y                       X – Y

                                         0         0                    0 – 0 = 0

                                                                        0 – 1 = 1
                                         0         1
                                                             (borrow 1, so that 10 – 1 = 1)

                                         1         0                    1 – 0 = 1

                                         1         1                    1 – 1 = 0


                 For example, let us subtract the binary number (111)  from (1000) .
                                                                        2            2
                                                          1     1
                                                      0  (10)  (10)  (10)  _____ Borrow

                                                      1   0     0    0

                                                  –       1     1    1
                                                      0   0     0    1



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