# How to scale down the operation +,-?

The plus sign + or minus sign - in LaTeX is too big for me. I want to scale down these binary operation symbol at once, so that whenever I type +, it corresponds to a more little + symbol. How can I do this? And what method to scale down the symbol is better? (By the way, I'm using mtpro2 now.)

My code:

\documentclass[12pt,a4paper,openany,fleqn]{book}
\usepackage[no-math]{xeCJK}
\setmainfont{TeX Gyre Termes Bold}
\usepackage[subscriptcorrection,slantedGreek,nofontinfo,zswash,mtphrb]{mtpro2}
\usepackage{bm}
\setCJKmainfont{cwTeX Q Ming} %just a Chinese font
\everymath{\displaystyle}
\begin{document}
results:\\
$a+b$\\
$\bm{\mathrm{a}}+\bm{\mathrm{b}}$\\
$\mbf {a+b}$ %MathTimePro2 original command
\end{document}


Result of test code:

• How much smaller should the symbol be?
– Mico
Feb 14, 2017 at 18:14
• I'm not sure should I better specified by percentage or an absolute size? In fact, I have no idea now. I need to trial-and-error and see the display. Maybe 80%. I guess.
– Eric
Feb 14, 2017 at 18:14
• Can you show the code you're using? If I do \usepackage{newtxtext,newtxmath}, with $(\mathbf{a}+\mathbf{b})$, I get a decidedly smaller plus sign Feb 14, 2017 at 18:32
• @egreg Wow! I haven't thought of that! I'm going to add my code.
– Eric
Feb 14, 2017 at 18:42
• @Eric As Boris says, somebody put their time into making a consistent math font (mtpro2, in this case). It wouldn't be too difficult to use the plus sign from newtxmath, but I'm not sure it's the right thing to do. Anyway, remove \everymath{\displaystyle}: it's one of the worst TeX hints around. And using a boldface font as main font is another very bad choice for your readers. Feb 14, 2017 at 18:56

1. Please do not do this. A good font was carefully designed by a font designer, who supposedly spent years in training and then designed fonts, carefully balancing readability, harmony and tradition. Making changes like this is like adding a moustache to a portrait in a gallery.

2. Instead, choose a font that corresponds to your tastes. Here is a catalog of free mathematical fonts: http://www.tug.dk/FontCatalogue/mathfonts.html. Linux libertine, http://www.tug.dk/FontCatalogue/linuxlibertine/, has smallish plus sign.

I don't recommend this approach of making + active in order to redefine it, because it will break things that are being added with \dimexpr and \numexpr. However, to that end, I have also provided \newplus to redefine the + and \oldplus to turn it off, restoring the original use.

\documentclass{article}
\usepackage{scalerel}
\let\svplus+
\catcode+=\active % Make + an active character
\def+{\mathbin{\ThisStyle{\vcenter{\hbox{$\SavedStyle\scaleto{\svplus}{5\LMpt}$}}}}}%
\catcode+=12 %
\def\newplus{\catcode+=\active }
\def\oldplus{\catcode+=12 }
\begin{document}
New: \newplus

$A + B \svplus C$

$\scriptstyle A + B \svplus C$

$\scriptscriptstyle A + B \svplus C$

Old: \oldplus

$A + B \svplus C$

$\scriptstyle A + B \svplus C$

$\scriptscriptstyle A + B \svplus C$
\end{document}


• +1 for using the scalerel package. :-)
– Mico
Feb 14, 2017 at 18:45
• @Mico Thanks. The \ThisStyle{...\SavedStyle...} approach to condensing \mathchoice options is so revolutionary ;^) that even TeXperts can't believe it. See comment following tex.stackexchange.com/questions/43978/proper-use-of-mathchoice/… Feb 14, 2017 at 18:50