Is the following argument valid or invalid? Justify your answer.
All prime numbers greater than 2 are odd.
The number a is not prime or a is less than or equal to 2.
Therefore, the number a is not odd.
The invalidity of an argument is always justified if given a counter argument. Let us take the number 9. The number “9” is not prime since it is divisible by 3. The “or” statement is therefore fulfilled. But 9 is odd since its not divisible by 2. Therefore the argument is invalid.