How to align 2 equations in fraction at `=`?

Question

I was trying to answer this question on another stackexchange forum, to say that they could use Latex instead, only to find I can't figure how to do this in Latex myself.

Is it possible to have 2 equations one in the numerator and one in denominator, be aligned at = in each? Here is MWE

\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
$\frac{\text{test} = 0.01}{\text{testing} = 0.01}$
\end{document}

Gives

I'd like these two to be aligned at =. Just like when one uses align* environment, except inside a fraction now.

\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{align*}
\text{test} &= 0.01 \\
\text{testing} &= 0.01
\end{align*}
\end{document}

TL 2022

Update Thanks for all the answers. Wish I can accept them all. I picked

\[
\begin{aligned}
\text{test}&=0.01 \\
\hline
\text{testing}&=0.01
\end{aligned}
\]

Because it was easiest for me to understand how it works. But all answers are really great.

Crosslink to some related question on fraction-align: 1 2 3 4 5 6 (although not at =) — user202729, Oct 29 '22 at 13:55

score 12 · Answer 1 · answered Oct 28 '22 at 22:10

12

Use some \phantoms and overlapping:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
$\frac{\text{test} = 0.01}{\text{testing} = 0.01}$
$\frac{\phantom{\text{testing}}\mathllap{\text{test}} = 0.01}{\text{testing} = 0.01}$
\end{document}

answered Oct 28 '22 at 22:10

Werner

603,163

Pretty trick. Good job and easy to use! You should propose a dedicated macro. – projetmbc Oct 29 '22 at 08:57
2

Here is one proposition of name \newcommand\samelenas[2]{\phantom{\text{#2}}\mathllap{\text{#1}}}. – projetmbc Oct 29 '22 at 09:05

score 9 · Answer 2 · answered Oct 28 '22 at 21:05

One possibility is to use an array.

\documentclass[12pt,a4paper]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\begin{array}{r@{}c@{}l}
\text{test}&{}={}&0.01 \\\hline
\text{testing}&{}={}&0.01
\end{array}
\end{equation*}
\end{document}

score 7 · Answer 3 · answered Oct 28 '22 at 21:29

Not to argue this as a preferred approach, but nonetheless, tabstackengine can achieve the desired result.

\documentclass[12pt]{article}
\usepackage[TABcline]{tabstackengine}
\usepackage{amsmath}
\stackMath
\begin{document}
\[
\setstackgap{S}{1pt}
\vcenter{\hbox{\alignShortstack{
\text{test} \mathstrut=& 0.01 \\
\TABcline{1-2}
\text{testing} \mathstrut=& 0.01}}} = 0
\]
\end{document}

egreg · Accepted Answer · 2022-10-29T08:57:42.423

This is, of course, not a fraction. But it's easy to emulate one.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
[
\begin{aligned}
\text{test}&=0.01 \
\hline
\text{testing}&=0.01
\end{aligned}
=
\frac{0.01}{0.01}
]
\end{document}

The spacing is not exactly the same, though.

Just for fun.

\documentclass{article}
\usepackage{amsmath}
\usepackage{booktabs}
\begin{document}
[
\setlength{\aboverulesep}{0.14ex}
\setlength{\belowrulesep}{0.22ex}
\begin{aligned}
\addlinespace[0.04ex]
\text{test}&=0.01 \
\midrule[0.4pt]
\text{testing}&=0.01
\end{aligned}
=
\frac{0.01}{0.01}
]
\end{document}

How to align 2 equations in fraction at `=`?

4 Answers4