Find the product :

$\dfrac{-13}{15} \times \dfrac{-25}{26}$

The product of two rational numbers $\dfrac{a}{b} \text{ and } \dfrac{c}{d}$ is given by $\dfrac{a}{b} \times \dfrac{c}{d} = \dfrac{a \times c}{b \times d}$.

Multiplying,

$\dfrac{-13}{15} \times \dfrac{-25}{26} = \dfrac{(-13) \times (-25)}{15 \times 26} \\[1em] = \dfrac{325}{390} \\[1em] = \dfrac{5}{6}$

Hence, $\mathbf{\dfrac{-13}{15} \times \dfrac{-25}{26} = \dfrac{5}{6}}$.