How to put question numbers in margin?

Question

I'm trying to put numbering to the solutions of my assignment in the margin of my document like so:

Ideally I'd like to enter the numbers "1.", "2.", ... etc. manually, i.e. not have them numbered automatically. How do I do this? I'm using a modified article class.

Answer 1

It seems to me that you are just using a normal enumerate environment to do that.

So, to achieve what you want

1. Load the package enumitem and add the optional argument [leftmargin=\labelsep] to your enumerate environment as in

   \begin{enumerate}[leftmargin=\labelsep]
   

   to have your label in the margin.

2. Simply use the optional argument of \item to manually specify your number as in

   \item[3.] Let $(x_n)$ be a sequence such that $x_n>0$
   

MWE (don't load the showframe package in your document, I've used it just to show the margins)

\documentclass{article}
\usepackage{enumitem}
\usepackage{showframe} % just to show the margins

\begin{document}

\begin{enumerate}[leftmargin=\labelsep]
  \item[3.] Let $(x_n)$ be a sequence such that $x_n>0$
  \[y_n=\frac{1}{\frac{1}{x_1}+}\]
  \begin{enumerate}
    \item Suppose that $x_n$ is a convergent
  \end{enumerate}
\end{enumerate}

\end{document} 

Output

---

If you instead use [leftmargin=0pt] you will obtain

while, with [leftmargin=*] the result is