I. Topic:
Truth Value and Negation MODULE #2
II. Objectives: At the end of the session, the students must be able to 1. Define truth value. 2. Define counterexample. 3. Negate statements. III. References: Synergy for Success in Mathematics pp. 255  256 IV. Motivation:
If a plane figure is a square, then it has exactly three sides. Is it true or false?
V. Lesson Proper:
DEFINITION:
The
truth value
of a statement is a value or attribute corresponding to the truth or falsehood of the statement. Example: 1. If an object is a triangle, then it has three sides and three corners.  TRUE 2. If today is Monday, then tomorrow is Tuesday.
–
TRUE 3. If an animal is a bird, then it can fly.  FALSE
DEFINITION:
A
counterexample
is an example that proves that a statement is not always true.
STATEMENT COUNTEREXAMPLE 1. If a number is divisible by 2, then it is divisible by 4 6 2. If an animal is a mammal, then it lives on land whale
DEFINITION:
The
negation
of a statement gives the opposite truth value of the srcinal statement.
→
P Not P True
False
False
True HOW ARE STATEMENTS NEGATED? 1. Statements with linking verbs
Write the word “not” after the linking verb
Examples:
This lesson is interesting.
This lesson is not interesting.
Whole numbers are fractions
Whole numbers are not fractions 2.
Statements with the word “has” or “have”
 replace the word has with the phrase does not have 
replace the word have with the phrase “do not have”
Examples:
A square has three sides.
A square does not have three sides.
Mage heroes have powerful skills.
Mage heroes do not have powerful skills. 3. Statements without a linking verb or the words has or have a. Base form of the verb
Write the phrase “do not” before the verb
Examples:
Parallel lines intersect
Parallel lines do not intersect.
Vloggers earn a lot in youtube.
Vloggers do not earn a lot in youtube. b. Sform of the verb 
Write the phrase “do not” before the verb and remove the letter s/es
Examples:
A point indicates length.

A point does not indicate length.
A grandmaster player bans OP heroes.

A grandmaster player does not ban OP heroes. VI. GENERALIZATION:
The
truth value
of a statement is a value or attribute corresponding to the truth or falsehood of the statement.
A
counterexample
is an example that proves that a statement is not always true.
The
negation
of a statement gives the opposite truth value of the srcinal statement. VII. EVALUATION:
⊸
A. Determine the truth value of the following statements. If the statement is false, give a counterexample.
1. If a number is divisible by 5, then it is divisible by 10. 2. If a plane figure is a quadrilateral, then it has four equal sides 3. If a number is multiplied to itself, then the product is a positive number. 4. If a number is a multiple 9, then it is a multiple of 3. 5. If 1 is continuously subtracted from a number, the resulting differences will have decreasing values.
⊸
B. Give the negation of the following statements.
1. Mathematics is a very difficult subject. 2. A prime number has factors other than 1 and itself. 3. Perpendicular lines intersect at exactly two points. 4. The number 2 divides an odd number without a remainder. 5. Responsible students are bound to fail.