Rational numbers - definition and examples

A rational number is any number that can be expressed as the quotient or fraction p/q of two integers, p and q, with the denominator q not equal to zero.

Set of rational numbers is denoted by the letter ℚ

Formally, the set of rational numbers can be written in such a way:
ℚ $= \{ \frac{p}{q} : p,q \in ℤ \land q \neq 0 \}$

Example #1:

Each integer is also a rational number.
Every integer can be written as a fraction p/q .

$1= \frac{1}{1} = \frac{4}{4} = \frac{9}{9} = ...$
$6= \frac{6}{1} = \frac{12}{2} = \frac{24}{4} = ...$
$-2= \frac{-2}{1} = \frac{-4}{2} = \frac{-100}{50} = ...$
$0= \frac{0}{6} = \frac{0}{55} = \frac{0}{109} = ...$

Example #2:

examples of rational numbers
$-11, -3, -\frac{2}{7}, 0, 1\frac{6}{9}, 0,(3)$
all of these numbers can be written as a fraction:
$-11=\frac{-11}{1}$
$-3=\frac{-3}{1}$
$1\frac{6}{9}=\frac{15}{9}$
$0(3)=\frac{1}{3}$

Example #3:

sometimes even roots are rational numbers

$\sqrt{4} = 2 = \frac{2}{1}$
$\sqrt[3]{125} = 5 = \frac{5}{1}$