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2 | 2 |
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3 | 3 | Boolean algebra is used to do arithmetic with bits of values True (1) or False (0). |
4 | 4 | There are three basic operations: 'and', 'or' and 'not'. |
| 5 | +Special or derived operations are : 'NAND', 'NOR', 'XOR' and 'XNOR' |
| 6 | + |
| 7 | +AND : |
| 8 | +The AND operation in Boolean algebra gives a result of 1 (True) only when all the input variables are 1 (True). |
| 9 | +If any input is 0 (False), the output will be 0 (False). |
| 10 | + |
| 11 | +Symbol: · or ∧ |
| 12 | +Example: If A = “I study” and B = “I sleep early”, |
| 13 | +then A AND B means “I study and I sleep early”. |
| 14 | +------------------------------ |
| 15 | + |INPUT A | INPUT B | Output | |
| 16 | + ------------------------------ |
| 17 | + | 0 | 0 | 0 | |
| 18 | + | 0 | 1 | 0 | |
| 19 | + | 1 | 0 | 0 | |
| 20 | + | 1 | 1 | 1 | |
| 21 | + ------------------------------ |
| 22 | + |
| 23 | +OR : |
| 24 | +The OR operation gives a result of 1 (True) when at least one of the input variables is 1 (True). |
| 25 | +It gives 0 (False) only when all inputs are 0 (False). |
| 26 | + |
| 27 | +Symbol: + or ∨ |
| 28 | +Example : If A = “I study” and B = “I sleep early”, |
| 29 | +then A OR B means “I study or I sleep early”. |
| 30 | + |
| 31 | + ------------------------------ |
| 32 | + | INPUT A | INPUT B | Output | |
| 33 | + ------------------------------ |
| 34 | + | 0 | 0 | 0 | |
| 35 | + | 0 | 1 | 1 | |
| 36 | + | 1 | 0 | 1 | |
| 37 | + | 1 | 1 | 1 | |
| 38 | + ------------------------------ |
| 39 | + |
| 40 | +NOT: |
| 41 | +The NOT operation is a unary operation (works on one variable). |
| 42 | +It inverts the value of the variable — |
| 43 | +if the input is 1 (True), the output becomes 0 (False), and vice versa. |
| 44 | + |
| 45 | +Symbol: Overline ( ̅ ), ¬, or ! |
| 46 | +Example : If A = “It’s raining”, then NOT A means “It’s not raining”. |
| 47 | + |
| 48 | + ------------------------------ |
| 49 | + | A | A̅ | |
| 50 | + ------------------------------ |
| 51 | + | 0 | 1 | |
| 52 | + | 1 | 0 | |
| 53 | + ------------------------------ |
| 54 | + |
| 55 | +NAND: |
| 56 | +The NAND operation is the inverse of the AND operation. |
| 57 | +It gives an output of 0 (False) only when all inputs are 1 (True). |
| 58 | +For all other combinations, the output is 1 (True). |
| 59 | + |
| 60 | +Symbol: (A · B)̅ or ¬(A ∧ B) |
| 61 | +Example: |
| 62 | +If A = “I study” and B = “I sleep early”, |
| 63 | +then A NAND B means “It’s not true that I study and sleep early both.” |
| 64 | + |
| 65 | + |
| 66 | +------------------------------ |
| 67 | + | INPUT A | INPUT B | Output | |
| 68 | + ------------------------------ |
| 69 | + | 0 | 0 | 1 | |
| 70 | + | 0 | 1 | 1 | |
| 71 | + | 1 | 0 | 1 | |
| 72 | + | 1 | 1 | 0 | |
| 73 | + ------------------------------ |
| 74 | + |
| 75 | +NOR: |
| 76 | +The NOR operation is the inverse of the OR operation. |
| 77 | +It gives an output of 1 (True) only when all inputs are 0 (False). |
| 78 | +If any input is 1 (True), the output becomes 0. |
| 79 | + |
| 80 | +Symbol: (A + B)̅ or ¬(A ∨ B) |
| 81 | +Example : If A = “I study” and B = “I sleep early”, |
| 82 | +then A NOR B means “Neither I study nor I sleep early.” |
| 83 | + |
| 84 | +------------------------------ |
| 85 | + | INPUT A | INPUT B | Output | |
| 86 | + ------------------------------ |
| 87 | + | 0 | 0 | 1 | |
| 88 | + | 0 | 1 | 0 | |
| 89 | + | 1 | 0 | 0 | |
| 90 | + | 1 | 1 | 0 | |
| 91 | + ------------------------------ |
| 92 | + |
| 93 | +XOR: |
| 94 | +The XOR (Exclusive OR) operation gives an output of 1 (True) only when exactly one of the inputs is 1 (True). |
| 95 | +If both inputs are the same (both 0 or both 1), the output is 0 (False). |
| 96 | + |
| 97 | +Symbol: ⊕ or A XOR B |
| 98 | +Example: |
| 99 | +If A = “I study” and B = “I sleep early”, |
| 100 | +then A XOR B means “I study or I sleep early, but not both.” |
| 101 | + |
| 102 | +------------------------------ |
| 103 | + | INPUT A | INPUT B | Output | |
| 104 | + ------------------------------ |
| 105 | + | 0 | 0 | 0 | |
| 106 | + | 0 | 1 | 1 | |
| 107 | + | 1 | 0 | 1 | |
| 108 | + | 1 | 1 | 0 | |
| 109 | + ------------------------------ |
| 110 | + |
| 111 | +XNOR: |
| 112 | +The XNOR (Exclusive NOR) operation is the inverse of the XOR operation. |
| 113 | +It gives an output of 1 (True) when both inputs are the same — either both 0 or both 1. |
| 114 | +If the inputs are different, the output is 0 (False). |
| 115 | + |
| 116 | +Symbol: ⊙ or (A ⊕ B)̅ or A XNOR B |
| 117 | +Example: If A = “I study” and B = “I sleep early”, |
| 118 | +then A XNOR B means “Either I study and sleep early both, or neither I study nor sleep early.” |
| 119 | +------------------------------ |
| 120 | + | INPUT A | INPUT B | Output | |
| 121 | + ------------------------------ |
| 122 | + | 0 | 0 | 1 | |
| 123 | + | 0 | 1 | 0 | |
| 124 | + | 1 | 0 | 0 | |
| 125 | + | 1 | 1 | 1 | |
| 126 | + ------------------------------ |
5 | 127 |
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6 | 128 | * <https://en.wikipedia.org/wiki/Boolean_algebra> |
7 | 129 | * <https://plato.stanford.edu/entries/boolalg-math/> |
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