Btukfyl

My question is quite similar to this one, but I think a slightly different approach is needed.

I have a document with a lot of exercices and I'd like to add aswers and hints to them in a certain section.

I don't want to do this manually, since, if I add an exercice, I'll have to make that the answers and hints keep the right order. Also, it's possible that not all exercices have an answer and a hint with them, so the numbering of answers and hints should be completely dependent of the numbering of exercices.

I.e, things like

1. Some hint for exercice 1

2. Some hint for exercice 2

4. Some hint for exercice 4

99. Some hint for exercice 99

should be possible.

For example:

documentclass[12pt,a4paper]{article}

usepackage[dutch]{babel}

usepackage{amsthm}



newtheorem{ex}{Exercice}

newtheorem{ans}{} % Abbreviation for answer. No text needed because I just want numbers with the answers next to them.

newtheorem{hi}{} % Same here.



begin{document}



section{Algebra}

begin{ex}What is $1+3$?end{ex}

begin{hi}First consider $1+0$, $1+1$, $1+2$ and try to find a pattern.end{hi}

begin{ans}It's $4$!end{ans}



section{Grammar}

setcounter{ex}{0} % So the counter is set to zero when a new section begins.



begin{ex}The first letter of the alphabet?end{ex}

%No hint given here

begin{ans}Aend{ans}



section*{Answers}

subsection{Section Algebra}

%Answer should be here, but of course it isn't.



subsection{Section Grammar}

%Same.



section*{Hints}

subsection{Section Algebra}

%Hint here.



subsection{Section Grammar}

% No hint because I didn't ask Latex to do so.



end{document}

So in fact I need some magicCommandThatPutsAnswersAndHintsSomewhereElse. If there's more then one answer in a section, I'd like them to be numbered like theorems.

As you may have noticed in the example, I want the answers and hints in a subsection that refers to their section.

I face the same issue as you do. I create my exercises lists with two features: I can print it with the answers (for students) or with the solutions (for me; in this case, the answers disappear).

I will show you here pieces of my code (it is too huge and, believe me, is not worth to paste it as a whole here). So, let's start...

I created the commands problem where I state the problem and answer where I store the answer to each problem, as well as the environment solution where I store the solution to the problem (with the argument, I can set the number of columns to arrange the solution in order to make it more compact):

%-> Defining COUNTERS:

newcounter{problem}



%-> Defining the numbered environment for QUESTIONS, TESTS, EXERCISES, PROBLEMS, and CHALLENGES:

newcommand{problem}{%

    parbigskip

    refstepcounter{problem}

    noindenttextbf{theproblem}

    }



%-> Defining the environment for the ANSWERS to QUESTIONS

newcommand{answer}[1]{%

    letthefootnoterelax %... suppresses the footnote numbering

    footnote{textbf{theproblem-} #1}%

}



newififcols



%-> Defining the environment for the SOLUTIONS:

newenvironment{solution}[1]{%

        setlength{parindent}{0cm}

        vspace{-2.5mm}

        textbf{footnotesize Solution:}par

        vspace{-3mm}

        footnotesize

        ifnum #1 > 1

            colstrue

            begin{multicols}{#1}

            fi

    }{%

    ifcols

        end{multicols}

        fi

    colsfalse

    }

Lattar on, I create the Boolean ifshowans for which showanstrue can be commented out whenever I want to hide the solution and show the answer (in case I want to prin material for the students). Otherwise, it will print the solution and hide the answers:

%-> Defining the MATERIAL TYPE:

newififshowans

showanstrue

    ifshowans

        renewcommandanswer[1]{}

    else

        letsolutioncomment

        letendsolutionendcomment

    fi

Up to here, you can observe that in my case, I preferred to show the solutions in the footnotes. Since you want to display them at the end of the document, you should modify the answer command to something like this:

%-> Defining the environment for the ANSWERS to QUESTIONS

newcommand{answer}[1]{%

    lettheendnoterelax %... suppresses the endnote numbering

    endnote{textbf{ptype mnumber.theproblem-} #1}%

}

I hope this helps you.

Edit:

This is an example of use (my students are Brazilian, so the problems are stated in Portuguese... sorry for that):

problem

O dia 21 de dezembro marca o solstício de verão no hemisfério sul. Nesse dia do ano, as sombras das pessoas em São Paulo (SP) têm comprimento nulo. Em uma viagem a Brasília nesse dia, a sombra projetada no chão de uma pessoa em pé ao meio-dia local tem um comprimento de 23,7 cm. Sabendo que a altura da pessoa é de 1,73 m e que uma volta à Terra tem comprimento $C = 40 v{mil km}$, calcule a distância entre São Paulo e Brasília.

answer{870 km}



%---------- SOLUTION ----------%

begin{solution}{2}

Do triângulo formado pela pessoa, sua sombra e o raio de luz do Sol, tem-se

$$

    tantheta = frac{23,7}{173} = 0,137

       Rightarrow    

    theta = 7,80deg

$$



Por regra de três simples,

$$

    begin{array}{rcl}

        360deg     & rightarrow & 40 000 v{km}

        \

        7,80deg    & rightarrow & d

    end{array}

       Rightarrow    

    d = 870 v{km}

$$

end{solution}

Edit 2: I just removed some undefined (and meaningless) commands