Decimal on Divison

Question

The following example return value 0 at division of \x by \y

\documentclass{article}
\usepackage[spanish]{babel}
\usepackage[utf8x]{inputenc}
\newcommand{\x}{31}
\newcommand{\y}{45}
\begin{document}
    I need the decimal results of following division:
    \the\numexpr\x/\y\relax.
\end{document}

How can I fix that?

\numexpr returns an integer number and rounds. Therefore, the result of 31/45 is 1, not 0. — Heiko Oberdiek, Apr 05 '18 at 17:12
See the fp or xfp packages for real-number mathematics, for example. I believe pgf based packages also provide such facilities. — Steven B. Segletes, Apr 05 '18 at 17:13

score 5 · Accepted Answer · answered Apr 05 '18 at 17:37

\documentclass{article}
\usepackage{xfp}

\begin{document}

\fpeval{31/45}

\fpeval{round(31/45,5)}

\end{document}

The toolbox of xfp is quite extensive.

If you need the comma instead of the decimal period, use siunitx:

\documentclass{article}
\usepackage{xfp,siunitx}

\sisetup{output-decimal-marker={,}}

\begin{document}

\num{\fpeval{31/45}}

\num{\fpeval{round(31/45,5)}}

\end{document}

score 4 · Answer 2 · answered Apr 05 '18 at 17:22

4

\documentclass{article}
%\usepackage[spanish]{babel}
\usepackage[utf8x]{inputenc}
\newcommand{\x}{31}
\newcommand{\y}{45}
\makeatletter
\newcommand\MyDivide[2]{\strip@pt\dimexpr\numexpr#1*65536/#2 sp\relax}

\makeatother
\begin{document}
    I need the decimal results of following division:
    \MyDivide{\x}{\y}
\end{document}

oops sorry I had interchanged #1 and #2 first. So:

answered Apr 05 '18 at 17:22

Thanks. And if I wanna make another operation (+, - or *) with those number. How could be? – Andrey Vinajera Apr 05 '18 at 17:49
@AndreyVinajera perhaps start with answers there or there – Apr 05 '18 at 18:30
@AnderyVinajera the canonical answer nowadays is probably to use the xfp package from LaTeX3 team, as in egreg's answer. It does computations with 16 decimal digits of precision and provides exp, log, sin, cos... My own xint computes in arbitrary precision and with fractions exactly, and has a floating-point mode which like xfp is set at 16 digits per default, but you can set it to 24 digits... caveat is that currently (April 2018) only sqrt is available as math function. xintexpr's parser has very extended syntax allowing things such as add(x(x+3)(x+5), x=10..20). – Apr 06 '18 at 06:53

score 3 · Answer 3 · answered Apr 05 '18 at 17:35

3

Here's a LuaLaTeX-based solution.

% !TeX program = lualatex

\RequirePackage{luacode}
\begin{luacode}
function mycalc (prec,n)
   tex.sprint ( string.format ( "%."..prec.."f" , n) )
end
\end{luacode}

\documentclass{article}
\usepackage[spanish]{babel}
%% Show 5 digits of prec. by default:
\newcommand\mycalc[2][5]{\directlua{mycalc(#1,#2)}}

\begin{document}
\newcommand{\x}{31} 
\newcommand{\y}{45}

I need the decimal results of following division: \mycalc{\x/\y}.
\end{document}

answered Apr 05 '18 at 17:35

Mico

506,678

@AndreyVinajera - Observe that the method used in this answer works for all arithmetic operations, not just division. Assuming \a, \b, and \c are suitably defined, you could write \mycalc{\a^{\b}*\c}, etc. – Mico Apr 06 '18 at 07:09

AndréC · Answer 4 · 2018-04-05T18:56:17.840

The xlop package 0.26 allows you to do French divisions like this:

\documentclass{article}
\usepackage{xlop}

\begin{document}
“french”  division:

\opdiv{31}{45}
\end{document}

Output:

It can stop as soon as the period found

\documentclass{article}
\usepackage{xlop}

\begin{document}
With inline mode:
\opdiv[maxdivstep=5,style=text]{31}{45}

Stop with period detection:
\opdiv[period,style=text]{31}{45}
\end{document}

Output:

Star macros allow calculations to be performed without displaying the result. In the case of division, the \opdiv*{31}{45}{q}{r} macro stores the quotient (q) and the rest (r) in two parameters.

Three macros allow a control about precision. They allow to approximate a number giving the rank of the approximation. There are \opfloor (default approximate value), \opceil (excess approximate value), and \opround (rounding)

\documentclass{article}
\usepackage{xlop}

\begin{document}

Approximation:
\opdiv*[maxdivstep=15]{31}{45}{q}{r}
 \opfloor{q}{7}{a}
 \opceil{q}{10}{b}
 \opround{q}{13}{c}

\opprint{a}

\opprint{b}

\opprint{c}
\end{document}

Output:

Decimal on Divison

4 Answers4

Linked