Answer
$$4.66 \mathrm{MeV} $$
Work Step by Step
$\begin{aligned} Q_{4} =&\left({m_{235_U}} - {m_{231_{Th}}} -{m_{4_{He}}
}\right) c^{2} \\ \\ = &(235.0439 \mathrm{u}-231.0363 \mathrm{u}-4.0026 \mathrm{u})(931.5 \mathrm{MeV} / \mathrm{u}) \\ \\ =&4.66 \mathrm{MeV} \end{aligned}$
