The GetError( obj ) command returns the absolute uncertainty of the quantity-with-error obj.

$\mathrm{with}\left(\mathrm{ScientificErrorAnalysis}\right)\:$

$\mathrm{Quantity}\left(20.0\,0.1\right)$

$\mathrm{Quantity}\left(20.0\,0.1\right)$

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

$0.1$

$\mathrm{ScientificConstants}:-\mathrm{Constant}\left(h\right)$

$\mathrm{Constant}\left(h\right)$

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

$8.1\times {10}^{\mathrm{-42}}$