Answer
$\color{}{\text{reciprocal}}$
Work Step by Step
RECALL:
$\dfrac{a}{b} \div \dfrac{c}{d} = \dfrac{a}{b} \times \dfrac{d}{c}$
The quotient of two fractions is equal to the product of the first fraction and the reciprocal of the divisor (second fraction).
Thus, the missing expression in the given statement is:
$\color{}{\text{reciprocal}}$
