General ⇒ Random Number Generator for Worksheets?

[LaTexLearner]

Does LaTeX provide a way to insert random numbers into documents?

Say I wanted to create worksheets for little children so they could practice adding single digit numbers.

Ideally, they'd practice slightly different worksheets each time, in the same format, but with different numbers.

Sometimes the first question would be 2+3=___. But if the kid scored 15/20 and wanted to try again, I'd like to just print another document that mixed up the numbers so the first question on the next version might be 9+4=___ or ___+3=10.

Is this possible? If not, what would you suggest?

[PMouse]

Have you looked at pgfmath which provides the 'random' package (and others) that do PRNG stuff? Is that what you are looking for?

I've never used this, myself, but ran across it a few times thinking I could use it for something in the future.

[LaTexLearner]

I haven't, but I'm going to check that out.

Thanks!

[LaTexLearner]

I've been reading through the TikZ & PGF Manual Part VIII but, honestly, I can't make sense of it. The technical jargon is far beyond my current knowledge.

Is there a more non-technical introduction to random number generation that anybody knows of?

For the time being, I would like to create simple integer worksheets so I don't have to type something like this out by hand over and over and over.

2-5=
+3+(+6)=
__-5=-11
28/__=-4

[Stefan Kottwitz]

Here is a small example:

Code: Select all

\documentclass{article}
\usepackage{tikz}
\pgfmathsetseed{\number\pdfrandomseed}
\newcommand*{\NewNumbers}{%
  \pgfmathsetmacro{\A}{random(0,10)}
  \pgfmathsetmacro{\B}{random(0,10)}}
\begin{document}
\NewNumbers
\A +\B = ?

\NewNumbers
\A *\B = ?
\end{document}

\NewNumbers initializes to get new numbers for A and B. I chose random(0,10) for a random number between 0 and 10.

Stefan

[rais]

Hi,
I've fiddled around with Stefan's code a bit...

Code: Select all

\documentclass{article}
\usepackage{tikz}
\pgfmathsetseed{\number\pdfrandomseed}
\newcommand*\PlaceHolder{\rule{1.5em}{0.3pt}}
\newcommand*\MyOp{?}
\newif\ifRgoesF% reads: if result goes first
\newcommand*{\NewNumbers}{%
  \pgfmathsetmacro{\Op}{random(0,3)}% kind of operation + - * /
  \pgfmathsetmacro{\Le}{random(0,2)}% which part to leave out
  \pgfmathsetmacro{\A}{random(0,10)}%
  \pgfmathsetmacro{\B}{random(0,10)}%
  \ifnum\Op > 1
    \pgfmathsetmacro{\C}{int(\A*\B)}% multiplication (or division)
  \else
    \pgfmathsetmacro{\C}{int(\A+\B)}% addition (or substraction)
  \fi
  \ifcase \Op
    \renewcommand*\MyOp{+}%
    \RgoesFfalse % \A + \B = \C
  \or
    \renewcommand*\MyOp{-}%
    \RgoesFtrue % \C - \B = \A
  \or
    \renewcommand*\MyOp{\cdot}%
    \RgoesFfalse % \A * \B = \C
  \or
    \renewcommand*\MyOp{/}%
    \RgoesFtrue % \C / \B = \A
  \else
    \typeout{This should not have happened...don't know operation `\Op'}%
  \fi
  \[
    \ifcase \Le
      \PlaceHolder \MyOp \B = \ifRgoesF\A\else\C\fi
    \or
      \ifRgoesF
        \C \MyOp \PlaceHolder = \A
      \else
        \A \MyOp \PlaceHolder = \C
      \fi
    \or      
      \ifRgoesF\C\else\A\fi \MyOp \B = \PlaceHolder
    \else
      ? ?? ??? = ????
    \fi
  \]
}
\newcommand*\GetSomeEquations[1][20]{%
  \foreach \Lp in {1,...,#1}{%
    \NewNumbers
  }%
}
\begin{document}
\GetSomeEquations
\end{document}

The basic idea behind it is to calculate the result, say, of a multiplication, before converting this into a division to ensure the result of this division being an integer value.
Of course, I didn't catch `division by zero' yet (nor am I sure if I should). Consider \B randomly set to zero: the result (\C) of a multiplication will be set to zero, too, but in case of a division, you might get 0/0=__ or 0/__=(whatever \A was set to).
Then again, it might be interesting to see if your students can make any sense of one of those, as well.

KR
Rainer

[LaTexLearner]

@stefan_k and @rais

Thank you for your posts! I will try to make sense of them later today.

[LaTexLearner]

Code: Select all

\documentclass{article}
\usepackage{tikz}
\pgfmathsetseed{\number\pdfrandomseed}
\newcommand*{\NewNumbers}{%
  \pgfmathsetmacro{\A}{random(0,10)}
  \pgfmathsetmacro{\B}{random(0,10)}}
\begin{document}
\NewNumbers
\A +\B = ?

\NewNumbers
\A *\B = ?
\end{document}

I think I understand most of this except

1. \pgfmathsetseed{\number\pdfrandomseed}? What does that do?

2. Why must there be an asterisk (*) in \newcommand*{\Newnumbers}...

[Stefan Kottwitz]

1. Initializing the random number generator with a value.

2. * chooses a version of \newcommand that doesn't allow paragraph breaks in an argument. Can help to avoid errors.

Stefan

[LaTexLearner]

1. Initializing the random number generator with a value.

Heh, what does that mean?

Doesn't {random(0,10)} already create a random value?