Which rational number also belongs to the set of natural numbers?

a. 15

b. 0.1666 ...

c. - 12

d. 3/8

Answer: A) 15

A natural number is basically a counting number {1, 2, 3, 4, 5, ... } so any positive whole number. That is why 15 is the answer. Choices B and D are fractional values, so we can rule them out. We can rule out choice C because this value is negative.