In the Natural Units environment, the eval function is overloaded to evaluate an expression after removing the units, and then combine the result with the units.

For other properties, see the global function eval.

$\mathrm{with}\left(\mathrm{Units}\left[\mathrm{Natural}\right]\right)\:$

$\mathrm{velocity}≔\mathrm{sqrt}\left(2\mathrm{gn}\mathrm{height}\right)$

$\mathrm{velocity}≔\sqrt{2}\sqrt{\mathrm{height}}⟦\sqrt{\mathrm{gn}}⟧$

$\mathrm{eval}\left(\mathrm{velocity}\,\mathrm{height}=3\mathrm{ft}\right)$

$\frac{\sqrt{2}\sqrt{3}\sqrt{381}\sqrt{196133}}{5000}⟦\frac{m}{s}⟧$

$\mathrm{evalf}\left(\right)$

$4.234902778⟦\frac{m}{s}⟧$

$\mathrm{eval}\left(\mathrm{velocity}\,\mathrm{height}=0.03\mathrm{km}\right)$

$0.01732050808\sqrt{2}\sqrt{196133}\sqrt{5}⟦\frac{m}{s}⟧$

$\mathrm{evalf}\left(\right)$

$24.25693715⟦\frac{m}{s}⟧$