[Tex/LaTex] Error with \framebox inside $$


I'm new to LaTeX, and I'm having an issue with using \framebox inside an equation (denoted with $$ signs at the beginning and the end).

The text that I'm trying to box is the following:

1.5 \times 10^{- 5} \; Pa

However, once I put a \framebox around it, like so:

\framebox{1.5 \times 10^{- 5} \; Pa}

I get the following error:

./assignment1.tex:85: Missing $ inserted.

…where 85 points to the line where I put in the \framebox. Any ideas why this is happening?

Best Answer

boxed will not span an equation if it encloses an alignment point i.e., & . In such cases you can use Aboxed from mathtools. See the example below for illustration. Further, to typeset units, better use siunitx.

  \framebox{$1.5 \times 10^{- 5}\si{\pascal}$}
    &\boxed{1.5 \times 10^{- 5}\si{\pascal}}\\
    \Aboxed{\text{Pressure} &=1.5 \times 10^{- 5}\si{\pascal}}

enter image description here

A useful read will be this Q and its A