Characteristics of Rational and Irrational Numbers

The video tutorial explains the classification of numbers into subsets, focusing on rational and irrational numbers. It clarifies that irrational numbers cannot be expressed as a ratio, while rational numbers can. The example of -21 is used to demonstrate that it is a rational number, specifically an integer, as it can be expressed as a ratio (-21:1). The tutorial further distinguishes between integers, whole numbers, and natural numbers, emphasizing that -21 is an integer but not a natural or whole number.

What is the main characteristic of irrational numbers?

• They can be expressed as a ratio.

• They cannot be expressed as a ratio.

• They are always positive.

• They are always negative.

Which of the following is an example of a rational number?

• √2

• e

• -21:1

• π

What type of number is -21?

• Irrational number

• Integer

• Whole number

• Natural number

Which of the following is NOT a type of rational number?

• Integer

• Irrational number

• Natural number

• Whole number

What distinguishes whole numbers from natural numbers?

• Natural numbers include zero.

• Whole numbers are always negative.

• Natural numbers are always negative.

• Whole numbers include zero.

Which subset of numbers does not include negative numbers?

• Rational numbers

• Whole numbers

• Natural numbers

• Integers