Not able to show negative signs

Question

I have the following.

\item Arrange in ascending order (smallest to largest): $−6, −2, 0, 1, −5, 4, 3$

But this output does not have negative signs.

6, 2, 0, 1, 5, 4, 3

It shows negative in other places.

\item Evaluate $(-2)^2$

This output has a negative sign.

Evaluate (−2)²

What am I doing wrong here?

Thank you in advance.

Answer 1

The minus signs in $−6, −2, 0, 1, −5, 4, 3$ are not hyphens - (0x2d) but dashes − (0x2212). A dash is slightly longer than a hyphen.

Solution: Replace dashes with hyphens.

The minus sign in \item Evaluate $(-2)^2$ is already a hyphen.

Answer 2

If you're doing much copy-paste from word processors, then it's better to load

\usepackage[utf8]{inputenc}

in your LaTeX document. Then you can teach LaTeX new correspondences between Unicode characters and LaTeX set of known objects, in this case

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{newunicodechar}

%% the first is the “unknown minus” (U+2212), the second is a hyphen
\newunicodechar{−}{-}

\begin{document}
$−1$
\end{document}

How do you know there's something amiss? Look in the .log file: you should find several instances of something like

Missing character: There is no <E2> in font cmr10!
Missing character: There is no <88> in font cmr10!
Missing character: There is no <92> in font cmr10!

one for each “disappearing” minus sign. Indeed, if you don't load inputenc with the utf8 option, TeX just sees the three byte representation of U+2212, precisely the bytes 0xE2, 0x88 and 0x92 that don't correspond to a printable character, because the default TeX fonts have only 128 glyphs.

With utf8, but no \newunicodechar declaration you'd get an error:

! Package inputenc Error: Unicode char \u8:− not set up for use with LaTeX.

and you can so understand what went wrong: the minus sign is not understood. Copy it and use it for defining the correct \newunicodechar declaration.