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Mathematical Reasoning



 

AND

In logic, two statements can be combined to form a compound statement using the word "and".


Logic
is the study of reasoning, and it deals with statements that are either true or false. When attempting to determine the truth value of a compound statement, first determine the truth value (true or false) of each of the components of the statement.

The compound statement using "and" is true only when both statements (or facts) are true.

A square has 4 sides. (true)

A triangle has 3 sides. (true)

A square has 4 sides and a triangle has 3 sides. (true)

(T + T) = True

The compound statement using "and" is false when one  or both statements (or facts) are false.

A square has 3 sides. (false)

A triangle has 3 sides. (true)

A square has 3 sides and a triangle has 3 sides. (false)

(F + T) = False

 

Examples:

1.  A cat is an animal (true) and 2 + 2 = 4 (true). 
(T + T = T)

Since both facts are true, the entire sentence is true.

 

 

2. A nickel is a coin (true) and a nickel is worth 10 cents (false).   
(T + F = F)

Since the second fact is false, the entire sentence is false.

 

 

3.  5 + 2 = 6 (false) and a dog is a cat (false).   

 (F + F = F)

Since both facts are false, the entire sentence is false.

 

 

Remember: For a compound statement using "and" to be true, BOTH facts must be true.
 

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