Pgfmath code conflict

Question

I am using the following code, and it works except for the custom macro \QuadraticEquations.

However, it works in a stand alone file. Am I missing something obvious?

\documentclass{article}
\usepackage{mathtools}
\usepackage{enumitem}
\usepackage{tikz}

\newcommand*{\Difficulty}{10}%

\newcommand{\FracQuestion}[1]{%
    \foreach \i in {1,...,#1}{%
      \pgfmathtruncatemacro{\DenomDifficulty}{2*\Difficulty}%
      \pgfmathtruncatemacro{\Neum}{random(\Difficulty)}
      \pgfmathtruncatemacro{\Denom}{random(\DenomDifficulty)}
      \item $\dfrac{\Neum}{\Denom}$%
    }%
}%

\newcommand{\LinearSystem}[1]{%
    \foreach \i in {1,...,#1}{%
      \pgfmathtruncatemacro{\Xa}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\Ya}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\Za}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\Xb}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\Yb}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\Zb}{random(\Difficulty)}%
      \item $\begin{cases}\begin{aligned}%
                \Xa x + \Ya y &= \Za \\%
                \Xb x + \Yb y &= \Zb \\%
              \end{aligned}\end{cases}$%
    }%
}%


\newcommand{\QuadraticEquations}[3]{%
    \foreach \i in {1,...,#1}{%
      \pgfmathtruncatemacro{\rootI}{random(-\Difficulty,\Difficulty)}%
      \pgfmathtruncatemacro{\rootII}{random(-\Difficulty,\Difficulty)}%
      \pgfmathtruncatemacro{\A}{1)}%
      \pgfmathtruncatemacro{\B}{-\A*(\rootI+\rootII)}%
      \pgfmathtruncatemacro{\C}{\A*\rootI*\rootII}%
      \item $\A x^2 \pgfmathprintnumber[showpos]{\B} x \pgfmathprintnumber[showpos]{\C} = 0$%
    }%
}%

\newcommand{\QuadraticEquationsEqualRoots}[1]{%
    \foreach \i in {1,...,#1}{%
      \pgfmathtruncatemacro{\A}{random(\Difficulty)}%
      \pgfmathtruncatemacro{\B}{random(\Difficulty)}%
      \pgfmathsetmacro{\C}{(\B*\B)/(4*\A)}%
      \item $\A x^2 + \B x + \C = 0$%
    }%
}%

\begin{document}
\section{Random Fractions:}
\begin{enumerate}
  \FracQuestion{3}
\end{enumerate}

\section{Random 2x2 Linear Equations:}
\begin{enumerate}
  \LinearSystem{3}
\end{enumerate}

\section{Random Quadratic Equations:}
\begin{enumerate}
    \QuadraticEquations{3}
\end{enumerate}

\section{Random Quadratic Equations (Equal Roots):}
\begin{enumerate}
  \QuadraticEquationsEqualRoots{3}
\end{enumerate}
\end{document}

Answer 1

Just read the error that the compiler yields. You get

\begin{enumerate} on input line 66 ended by \end{document}. \end{document}

It means that for some reason, enumerate environment hasn't been closed. When you look at \QuadraticEquations's definition you can see that

\newcommand{\QuadraticEquations}[3]{%
    \foreach \i in {1,...,#1}{%
      \pgfmathtruncatemacro{\rootI}{random(-\Difficulty,\Difficulty)}%
      \pgfmathtruncatemacro{\rootII}{random(-\Difficulty,\Difficulty)}%
      \pgfmathtruncatemacro{\A}{1)}%
      \pgfmathtruncatemacro{\B}{-\A*(\rootI+\rootII)}%
      \pgfmathtruncatemacro{\C}{\A*\rootI*\rootII}%
      \item $\A x^2 \pgfmathprintnumber[showpos]{\B} x \pgfmathprintnumber[showpos]{\C} = 0$%
    }%
}%

defined the way that it requires from you 3 arguments whereas your macro needs only one, that's why \end{enumerate} is being swallowed and error occurs.

---

TL;DR

Replace

\newcommand{\QuadraticEquations}[3]

with

\newcommand{\QuadraticEquations}[1]