Lesson: Laws of Deductive Reasoning

In this lesson, we will learn how to use the law of detachment and the law of syllogism to reach logical conclusions from given statements.

Worksheet: 2 Questions

Q1:

Statement 1: If and are odd numbers, then is odd.

Statement 2: and are odd numbers.

What can we conclude about ?

Statement 3: If is an odd number, then is prime.

Statement 4: is an odd number.

Can we conclude is prime? Why?

Q2:

Given statements 3 and 4 below, which of the following statements is also true?

Statement 3: If is odd, then both and are odd.

Statement 4: If both and are odd, then is even.

Statement 5: If a shape is a square, then it has a right angle.

Statement 6: If a shape is a square, then it has a pair of parallel sides.

Shape has a right angle and a pair of parallel sides. What can we conclude about shape from the given statements?

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