Final answer:
The number 0.153 belongs to the subset of the real number system known as rational numbers.
Step-by-step explanation:
The number 0.153 belongs to the subset of the real number system known as rational numbers. Rational numbers are numbers that can be expressed as a fraction, where the numerator and the denominator are both integers.
To determine if a number is rational, we can check if we can write it as a fraction. For example, we can write 0.153 as 153/1000, which is a fraction. Therefore, it is a rational number.
Other examples of rational numbers include -2, 3/4, and 5.