Q:

Getting rid of space around flashcards in the flashcard class

Consider the sample document given in the (chapter 3) of the documentation of the flashcards class.
\documentclass[avery5388,grid,frame]{flashcards}
\cardfrontstyle[\large\slshape]{headings}
\cardbackstyle{empty}
\begin{document}
\cardfrontfoot{Functional Analysis}
\begin{flashcard}[Definition]{Norm on a Linear Space \\ Normed Space}
A linear/vector space with a norm is called a \emph{normed}
\end{flashcard}

\begin{flashcard}[Definition]{Inner Product}
  Let $X$ be a complex linear space. An \emph{inner product} a mapping that associates to each pair of vectors $x$, $y$ denoted $(x,y)$, that satisfies Additivity, Homogeneity, Symmetry and positive Definiteness.
\end{flashcard}
\end{document}

When printing those flashcards I don't want to spend extra time also cutting of the extra white space around the flashcards themselves.
However, trying to reduce the margins with the geometry package clashes with the class options, since it already uses this package and \setlength{\textheight}{854} also doesn't help.
How can I tackle this problem?
Edit: It would also suffice if all margins would be the same length, then I could just enlarge the document before printing, effectively getting rid of the white space, too.

A:

From the documentation, you have one option \setlength{\cardmargin}{0 pt} on page ten that allows you to change the margins.
Edit: Update the answer with the info in the comments.
You can set the margins of the paper and the size of the card according to the paper so that you have no margins.
Below there's the code that fits 3 cards in one A4-size paper without any margins.
\documentclass[avery5388,grid,frame]{flashcards}
\cardfrontstyle[\large\slshape]{headings}
\cardbackstyle{empty}
\usepackage{geometry}
\geometry{
        a4paper,
        total={210mm,297mm},
        left=0mm,
        top=0mm,
}
%
\setlength{\cardheight}{99mm}  % 99=297/3
\setlength{\cardwidth}{210mm}
\setlength{\topskip}{0mm}
%

\begin{document}
\cardfrontfoot{Functional Analysis}
\begin{flashcard}[Definition]{Inner Product}
Let $X$ be a complex linear space. An \emph{inner product} a mapping that associates to each pair of vectors $x$, $y$ denoted $(x,y)$, that satisfies Additivity, Homogeneity, Symmetry and positive definiteness.
\end{flashcard}
\begin{flashcard}[Definition]{Inner Product}
Let $X$ be a complex linear space. An \emph{inner product} a mapping that associates to each pair of vectors $x$, $y$ denoted $(x,y)$, that satisfies Additivity, Homogeneity, Symmetry and positive definiteness.
\end{flashcard}
\begin{flashcard}[Definition]{Inner Product}
Let $X$ be a complex linear space. An \emph{inner product} a mapping that associates to each pair of vectors $x$, $y$ denoted $(x,y)$, that satisfies Additivity, Homogeneity, Symmetry and positive definiteness.
\end{flashcard}
\end{document}

If you use a different paper size, you can adjust it in the options of the geometry package.

