Conjunction AND Topic Index | Geometry Index | Regents Exam Prep Center

 In logic, a conjunction is a compound sentence formed by combining two sentences (or facts) using the word "and."   A conjunction is true only when BOTH sentences (or facts) are true.

Examples:

1.  "Blue is a color and 7 + 3 = 10."  (T and T = T)
Since both facts are true, the entire sentence is true.

2.  "One hour = exactly 55 minutes and one minute = exactly 60 seconds.
(F and T = F)  Since the first fact is false, the entire sentence is false.

3.  "3 + 4 = 6 and all dogs meow."  (F and F = F)
Since both facts are false, the entire sentence is false.

Mathematicians often use symbols and tables to represent concepts in logic.  The use of these variables, symbols and tables creates a shorthand method for discussing logical sentences.

Truth table for conjunction (and):
(notice the symbol used for "and" in the table below)

 T T T T F F F T F F F F

A truth table is a pictorial representation of all of the possible outcomes of the truth value of a compound sentence.  Letters such as and are used to represent the facts (or sentences) within the compound sentence.

 Remember:   For a conjunction (and)  to be true, BOTH facts  must be true.

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