Question

Is 23 a rational number?

Answer 1

Yes. `23 = 23/1 = 46/2 = 69/3`
A rational number can be written as a fraction.

Explanation:

A Rational number is a Real number which can be written as a fraction with the numerator and denominator both being integers. (whole numbers)
`a/b, b != 0` (The denominator may not be 0)

Rational numbers include:
all the common fractions,
all the terminating decimals (like 3.875)
all the recurring decimals (like 4.121212....)
all the integers (....-3, -2, -1, 0, 1, 2, 3 ....)
all the counting (whole) numbers (0, 1, 2, 3 ....)
all the natural numbers (1, primes and composites) (1, 2, 3, 4, .....)

Which real numbers are not rational? -the irrational numbers:

Square roots of numbers which are not perfect squares `sqrt20`
Cube roots of numbers which are not perfect cubes `root(3)12`