I want to `\foreach` on a list and create task (via package [`tasks`](https://www.ctan.org/pkg/tasks)) inside a question. A MWE:

```
\documentclass{article}
\usepackage[magyar]{babel}
\usepackage[utf8x]{inputenc}
\usepackage{t1enc}
\usepackage{exsheets}
\usepackage{pgffor}
\usepackage{fp}
\def\pontlist{
2/3/1/4/,
5/1/-4/3/,
2/7/11/10/,
4/-3/5/7/,
-4/4/5/-7/,
-4/-4/4/4/,
3/7/-3/10/,
-1/-2/3/4/,
-1/3/-2/1/
}
\newcommand{\felezopont}[4]{
  \FPeval{\resx}{round( ( (#1)+(#3) )/2,1)}
  \FPeval{\resy}{round( ( (#2)+(#4) )/2,1)}
  \task $A(#1;#2)$, $B(#3;#4)$
  {$(\resx;\resy)$}
}
\begin{document}
\begin{question}
  Határozd meg a következő pontpárok felezőpontját!
  \begin{tasks}
    \foreach \ax/\ay/\bx/\by in \pontlist {
      \felezopont{\ax}{\ay}{\bx}{\by}
    }
  \end{tasks}
\end{question}
\end{document}

```

Without `\begin{tasks} ... \end{tasks}` works well but the use of `tasks` environment causes an error:

```
! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...

l.33 \end{question}

```

What do I use wrong?
['https://tex.stackexchange.com/questions/354242', 'https://tex.stackexchange.com', 'https://tex.stackexchange.com/users/8836/']
It is a question of whether your text font has such a character. If you look in the log file you will find 

> 
> `Missing character: There is no π (U+03C0) in font [lmroman12-regular]:+tlig;!`
> 
> 
> 

In your case pi represents a mathematical entity and in normal text with unicode input you can use

```
  This is $π$.

```

if you load the package `unicode-math`. 

The `siunitx` package provides a direct interpretation of `\pi` in numbers so you can write 

```
\SI{\pi/2}{\radian}

```

If you insert the pi character, even with `unicode-math` it will complain with 

> 
> `! Invalid token 'π' in numerical input.`
> 
> 
> 

in the log file.
This typesets pi and gives an error message when using \SI. SI does not recognize pi as the number 3.14159.... 

```
\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{fontspec}
\setmainfont{DejaVu Serif}
\usepackage{siunitx} %Einheiten

\begin{document}
    This is π. 
   \SI{π/2}{\radian} %Here latex hangs up
\end{document}

```