Approximation error
= Approximation error
{title2=$x_{\mathrm{approx}}-x$}
For a numerical reference value $x$ and a computed value $x_{\mathrm{approx}}$, the signed <approximation error> is $x_{\mathrm{approx}}-x$. Stating the reference matters: comparison with a measured value assesses agreement with that value, rather than with an unknown exact value.