You multiply two rational numbers by multiplying numerators and denominators with each other. So, you have
[tex] \dfrac{a}{b} \times \dfrac{c}{d} = \dfrac{ac}{bd} [/tex]
A rational number is a fraction where both numerator and denominator are integers. Since the product of two integers is an integer, the result fraction is also a rational number, because both [tex] ac [/tex] and [tex] bd [/tex] are integers.
