Answer
Undefined
Work Step by Step
Consider if $b, c, $ or $d$ equals zero. Then in one of the expressions $\frac{a}{b}\div\frac{c}{d}$ or $\frac{a}{b}\cdot\frac{d}{c}$, the denominator of one of the fractions will be zero. Dividing by zero will yield an undefined result, so it will not work.
