Convert the following into basic units:
$(i)$ $28.7\, pm$
$(ii)$ $15.15\, pm$
$(iii)$ $25365\, mg$

$(i)$ $28.7\, pm$
$1\, pm = 10^{-12}\, m$
$\therefore 28.7\, pm = 28.7 \times 10^{-12}\, m = 2.87 \times 10^{-11}\, m$
$(ii)$ $15.15\, pm$
$1\, pm = 10^{-12}\, m$
$\therefore 15.15\, pm = 15.15 \times 10^{-12}\, m = 1.515 \times 10^{-11}\, m$
$(iii)$ $25365\, mg$
$1\, mg = 10^{-3}\, g$ and $1\, g = 10^{-3}\, kg$, so $1\, mg = 10^{-6}\, kg$
$\therefore 25365\, mg = 25365 \times 10^{-6}\, kg = 2.5365 \times 10^{-2}\, kg$