Fonte: https://github.com/afmachado/com.numix.calculator/tree/master/app/src/main/res/values-pt-rBR

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2007 The Android Open Source Project
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
          http://www.apache.org/licenses/LICENSE-2.0
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<resources>
    <!-- Application name -->
    <string name="app_name">Numix Calculator</string>
    <!-- If there is a syntax error in the user entered calculation, an error dialog will appear.  This is the title. -->
    <string name="error">Erro :(</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit0">0</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit1">1</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit2">2</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit3">3</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit4">4</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit5">5</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit6">6</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit7">7</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit8">8</string>
    <!-- Displayed numbers for the digit buttons -->
    <string name="digit9">9</string>
    <!-- Button name on screen to delete the last entered digit or operator -->
    <string name="del">EXCLUIR</string>
    <!-- Button name on screen to clear the entire calculation field. [CHAR LIMIT=6] -->
    <string name="clear">LIMPAR</string>
    <!-- Do not translate. Unicode division sign; don't translate. Displayed as button on screen. -->
    <string name="div">\u00f7</string>
    <!-- Do not translate. Unicode multiplication sign; don't translate. Displayed as button on screen. -->
    <string name="mul">\u00d7</string>
    <!-- Do not translate. Plus sign, displayed as button on screen -->
    <string name="plus">+</string>
    <!-- Do not translate. Unicode minus sign; don't translate. Displayed as button on screen. -->
    <string name="minus">\u2212</string>
    <!-- Do not translate. Equal sign; don't translate. Displayed as button on screen. -->
    <string name="equal">=</string>
    <!-- Do not translate. Down arrow; don't translate. Displayed as button on screen. -->
    <string name="enter">\u2193</string>
    <!-- Displayed on buttons on screen for the sin function. -->
    <string name="sin">sin</string>
    <!-- Do not translate. What we replace translated SIN with for calculating sin.-->

    <!-- Displayed on buttons on screen for the cos function. -->
    <string name="cos">cos</string>
    <!-- Do not translate. What we replace translated COS with for calculating cos. -->

    <!-- Displayed on buttons on screen for the tan function. -->
    <string name="tan">tan</string>
    <!-- Do not translate. What we replace translated TAN with for calculating tan. -->

    <!-- Do not translate. Unicode pi sign; don't translate. Displayed as button on screen. -->
    <string name="pi">\u03c0</string>
    <!-- Displayed on buttons on screen for the e function. -->
    <string name="e">e</string>
    <!-- Do not translate. What we replace translated e with for calculating e. -->

    <!-- Displayed on buttons on screen for the ln function. -->
    <string name="ln">ln</string>
    <!-- Do not translate. What we replace translated ln with for calculating ln. -->

    <!-- Displayed on buttons on screen for the log function. -->
    <string name="lg">log</string>
    <!-- Do not translate. What we replace translated lg with for calculating lg. -->

    <!-- Displayed on buttons on screen for a left parenthesis. -->
    <string name="leftParen">(</string>
    <!-- Displayed on buttons on screen for a right parenthesis. -->
    <string name="rightParen">)</string>
    <!-- Do not translate. Unicode square root sign; don't translate. Displayed on button on screen. -->
    <string name="sqrt">\u221a</string>
    <!-- Do not translate. Displayed on buttons on screen. -->
    <string name="power">^</string>
    <!-- Do not translate. -->
    <string name="factorial">!</string>
    <!-- Menu item text to take user to the screen with the basic digits and operators. -->
    <string name="basic">Painel Básico</string>
    <!-- Menu item text to take user to the screen with the advanced functions, such as sin, cos, ln, log, etc. -->
    <string name="advanced">Painel Avançado</string>
    <!-- Menu item text to clear the calculation history. -->
    <string name="clear_history">Limpar histórico</string>
    <!-- Toast shown when text is copied to the clipboard. -->
    <string name="text_copied_toast">Texto copiado.</string>

    // new

    <!--Content descriptions for accessibility. These strings will be read aloud to users who are using the calculator with
    accessibility features enabled and should reflect the mathematical concept instead of a direct representation of what is shown
    on the button-->
    <string name="leftParenDesc">abre parêntese</string>
    <string name="rightParenDesc">fecha parêntese</string>
    <string name="factorialDesc">fatorial</string>
    <string name="lnDesc">logaritmo natural</string>
    <string name="lgDesc">logaritmo</string>
    <string name="sqrtDesc">raiz quadrada</string>
    <string name="divDesc">dividir</string>
    <string name="mulDesc">multiplicar</string>
    <string name="plusDesc">somar</string>
    <string name="minusDesc">subtrair</string>
    <string name="dotDesc">vírgula</string>
    <string name="powerDesc">potência</string>
    <string name="delDesc">excluir</string>
    <string name="clearDesc">limpar</string>
    <string name="tanDesc">tangente</string>
    <string name="sinDesc">seno</string>
    <string name="cosDesc">cosseno</string>
    <string name="eDesc">número de Euler</string>
    <string name="piDesc">pi</string>
    <string name="equalDesc">igual</string>

    <!--Content descriptions for accessibility used as keys when determining which mathematical
    concept description to speak when accessibility features are enabled. Order of the array is
    important. -->
    <string-array name="operators" translatable="false">
        <item>(</item>
        <item>)</item>
        <item>!</item>
        <item>ln</item>
        <item>log</item>
        <item>\u221a</item>
        <item>\u00f7</item>
        <item>\u00d7</item>
        <item>+</item>
        <item>\u2212</item>
        <item>.</item>
        <item>^</item>
        <item>tan</item>
        <item>sin</item>
        <item>cos</item>
        <item>\u03c0</item>
        <item>=</item>
    </string-array>

    <!--Content descriptions for accessibility. These strings will be read aloud to users who
     are using the calculator with accessibility features enabled and hover over the edit text
     field. These should reflect the mathematical concept instead of a direct representation of
     what is shown in the text field. Order of the array is important.-->
    <string-array name="operatorDescs">
        <!-- Description for mathematical ( [CHAR LIMIT=200]-->
        <item>abre parêntese</item>
        <!-- Description for mathematical ) [CHAR LIMIT=200]-->
        <item>fecha parêntese</item>
        <!-- Description for mathematical ! (factorial) function [CHAR LIMIT=200]-->
        <item>fatorial</item>
        <!-- Description for mathematical ln [CHAR LIMIT=200]-->
        <item>logaritmo natural</item>
        <!-- Description for mathematical log [CHAR LIMIT=200]-->
        <item>logaritmo</item>
        <!-- Description for mathematical square root [CHAR LIMIT=200]-->
        <item>raiz quadrada</item>
        <!-- Description for mathematical / [CHAR LIMIT=200]-->
        <item>dividido por</item>
        <!-- Description for mathematical x [CHAR LIMIT=200]-->
        <item>multiplicado por</item>
        <!-- Description for mathematical + [CHAR LIMIT=200]-->
        <item>somado com</item>
        <!-- Description for mathematical - [CHAR LIMIT=200]-->
        <item>subtraído de</item>
        <!-- Description for mathematical . [CHAR LIMIT=200]-->
        <item>&#160;point&#160;</item>
        <!-- Description for mathematical ^ [CHAR LIMIT=200]-->
        <item>potência</item>
        <!-- Description for mathematical TAN [CHAR LIMIT=200]-->
        <item>tangente</item>
        <!-- Description for mathematical SIN [CHAR LIMIT=200]-->
        <item>seno</item>
        <!-- Description for mathematical COS [CHAR LIMIT=200]-->
        <item>coseno</item>
        <!-- Description for mathematical PI [CHAR LIMIT=200]-->
        <item>pi</item>
        <!-- Description for mathematical = [CHAR LIMIT=200]-->
        <item>igual</item>
    </string-array>

    //new


    <string name="square_root_symbol">"√¯¯"</string>
    <string name="delete_numbers">"\u21D0"</string>
    <string name="exp">"^"</string>

    <string name="menu_about">"Sobre"</string>
    <string name="menu_settings">"Configurações"</string>

    <string name="title_activity_settings">"Configurações"</string>
    <string name="theme_category_summary">"Mudar a aparência da calculadora"</string>
    <string name="theme_summary">"Escolha um tema"</string>
    <string name="history">"O histórico está disponível somente na versão PRO. Desculpe!"</string>
    <string name="theme_title">"Tema"</string>
    <string name="function_category_summary">"Mudar a funcionalidade da calculadora"</string>
    <string name="function_category_title">"Função"</string>
    <string name="precision_summary">"Escolha o tamanho do resultado a ser mostrado (AVISO: se você configurar este número acima de 500, o desempenho poderá cair!)"</string>
    <string name="precision_title">"Precisão"</string>
    <string name="angle_summary">"Escolha calcular em graus ou radianos"</string>
    <string name="angle_title">"Graus/radianos"</string>

    <string name="title_activity_about">"Sobre"</string>
    <string name="clean">"Limpar"</string>
    <string name="or">"OU"</string>
    <string name="playstore">"<u>Avalie este app! Isso nos ajuda muito a manter as atualizações constantes.</u>"</string>
    <string name="playstoredon">"<u>Por favor instale a versão de doador deste app na playstore se você puder nos ajudar.</u>"</string>
    <string name="mail">"<u>Nos envie um retorno ou sugestões.</u>"</string>
</resources>