Real numbers include whole numbers, rational numbers, irrational numbers, can be positive, negative, or zero.
Natural numbers are whole, non-negative numbers.
Integers are whole numbers that are either positive or negative.
Rational numbers are positive or negative numbers that can be written as a ratio or a fraction.
Irrational numbers are numbers that cannot be written as a fraction. Instead, it can be written as a decimal.
10.) - 21.983 ⇒ real number, irrational number
11.) π ⇒ irrational number, real number
12.) 21/7 ⇒ rational number, real number, whole number, natural number, integer. This is because 21/7 = 3.
