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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
Tech Funda
The binary number system was invented by Gottfried Lebiniz in 1679.
Recap
A number system is method of counting.
The decimal number system consists of ten digits from 0 to 9.
The binary number system consists of two digits 0s and 1s.
The octal number system consists of eight digits from 0 to 7.
The hexadecimal number system consists of 16 digits from 0 to 9 and A to F.
Number System 13

