#### Answer

The product of two or more fractions is the product of their numerators
divided by the product of their denominators.
$\displaystyle \frac{a}{b}\cdot\frac{c}{d}=\frac{a\cdot c}{b\cdot d}$

#### Work Step by Step

The product of two or more fractions is the product of their numerators
divided by the product of their denominators.
$\displaystyle \frac{a}{b}\cdot\frac{c}{d}=\frac{a\cdot c}{b\cdot d}$
Also, you can divide numerators and denominators by common factors before performing multiplication.
Example
$\displaystyle \frac{2}{3}\cdot\frac{4}{5}=\frac{2\cdot 4}{3\cdot 5}=\frac{8}{15}$
Example (reduce before multiplying)
$\displaystyle \frac{15}{17}\cdot\frac{51}{80}=\frac{3\times(5)}{[17]}\cdot\frac{3\times[17]}{(5)\times 16}=\frac{3 }{1}\cdot\frac{3 }{ 16}$
$=\dfrac{3\times 3}{1\times 16}=\dfrac{9}{16}$