Find the cube of $2\dfrac{1}{2}$

$\Big(2\dfrac{1}{2}\Big)^3\\[1em] = \Big(\dfrac{5}{2}\Big)^3\\[1em] = \Big(\dfrac{5}{2} \times \dfrac{5}{2} \times \dfrac{5}{2}\Big)\\[1em] = \dfrac{125}{8}\\[1em] = 15\dfrac{5}{8}$

$\Big(2\dfrac{1}{2}\Big)^3 = 15\dfrac{5}{8}$