Moodle formulas question (a test case for inconsistency verifying student answer)

Moodle_formulas_question.xml

<?xml version="1.0" encoding="UTF-8"?>
<quiz>
<!-- question: 3039285  -->
  <question type="formulas">
    <name>
      <text>random validation error test case</text>
    </name>
    <questiontext format="html">
      <text><![CDATA[<b>Please use normal decimal syntax:</b><br><br>{#A}<br><br>{#B}<br><br>{#C}<br><br>{#D}<br>]]></text>
    </questiontext>
    <generalfeedback format="html">
      <text></text>
    </generalfeedback>
    <defaultgrade>4</defaultgrade>
    <penalty>0.3333333</penalty>
    <hidden>0</hidden>
    <idnumber>495963</idnumber>
    <correctfeedback format="html">
      <text>תשובתך נכונה.</text>
    </correctfeedback>
    <partiallycorrectfeedback format="html">
      <text>תשובתך נכונה חלקית.</text>
    </partiallycorrectfeedback>
    <incorrectfeedback format="html">
      <text>תשובתכם אינה נכונה</text>
    </incorrectfeedback>
    <shownumcorrect/>
<varsrandom><text>a3={1:8:0.01};
b3={1:7};
a1={1:8:0.01};
b1={1:7};
a2={1:8:0.01};
b2={1:7};

a4={1:8:0.01};
b4={1:7};</text>
</varsrandom>
<varsglobal><text>c1=a1*pow(10,-b1);

c2=a2*pow(10,-b2);



c4=a4*pow(10,-b4);</text>
</varsglobal>
<answernumbering><text>none</text>
</answernumbering>
<answers>
 <partindex>
  <text>0</text>
 </partindex>
 <placeholder>
  <text>#A</text>
 </placeholder>
 <answermark>
  <text>1</text>
 </answermark>
 <answertype>
  <text>10</text>
 </answertype>
 <numbox>
  <text>1</text>
 </numbox>
 <vars1>
  <text></text>
 </vars1>
 <answer>
  <text>[c1]</text>
 </answer>
 <vars2>
  <text></text>
 </vars2>
 <correctness>
  <text>_err == 0</text>
 </correctness>
 <unitpenalty>
  <text>0</text>
 </unitpenalty>
 <postunit>
  <text></text>
 </postunit>
 <ruleid>
  <text>1</text>
 </ruleid>
 <otherrule>
  <text></text>
 </otherrule>
 <autocomplete>
  <text>0</text>
 </autocomplete>
 <subqtext format="html">
<text><![CDATA[<p style="direction: ltr;">{a1}•10<sup>-{b1}</sup>=&nbsp; {_0}&nbsp; &nbsp; &nbsp;&nbsp;</p>]]></text>
 </subqtext>
 <feedback format="html">
<text></text>
 </feedback>
 <correctfeedback format="html">
<text></text>
 </correctfeedback>
 <partiallycorrectfeedback format="html">
<text></text>
 </partiallycorrectfeedback>
 <incorrectfeedback format="html">
<text></text>
 </incorrectfeedback>
</answers>
<answers>
 <partindex>
  <text>1</text>
 </partindex>
 <placeholder>
  <text>#B</text>
 </placeholder>
 <answermark>
  <text>1</text>
 </answermark>
 <answertype>
  <text>10</text>
 </answertype>
 <numbox>
  <text>1</text>
 </numbox>
 <vars1>
  <text></text>
 </vars1>
 <answer>
  <text>[c2]</text>
 </answer>
 <vars2>
  <text></text>
 </vars2>
 <correctness>
  <text><![CDATA[_relerr < 0.01]]></text>
 </correctness>
 <unitpenalty>
  <text>0</text>
 </unitpenalty>
 <postunit>
  <text></text>
 </postunit>
 <ruleid>
  <text>1</text>
 </ruleid>
 <otherrule>
  <text></text>
 </otherrule>
 <autocomplete>
  <text>0</text>
 </autocomplete>
 <subqtext format="html">
<text><![CDATA[<p style="direction: ltr;">{a2}•10<sup>-{b2}</sup>=&nbsp; {_0}&nbsp; &nbsp; &nbsp;<br></p>]]></text>
 </subqtext>
 <feedback format="html">
<text></text>
 </feedback>
 <correctfeedback format="html">
<text></text>
 </correctfeedback>
 <partiallycorrectfeedback format="html">
<text></text>
 </partiallycorrectfeedback>
 <incorrectfeedback format="html">
<text></text>
 </incorrectfeedback>
</answers>
<answers>
 <partindex>
  <text>2</text>
 </partindex>
 <placeholder>
  <text>#C</text>
 </placeholder>
 <answermark>
  <text>1</text>
 </answermark>
 <answertype>
  <text>10</text>
 </answertype>
 <numbox>
  <text>1</text>
 </numbox>
 <vars1>
  <text>e5=a3*pow(10,-b3);</text>
 </vars1>
 <answer>
  <text>[e5]</text>
 </answer>
 <vars2>
  <text></text>
 </vars2>
 <correctness>
  <text>_relerr == 0</text>
 </correctness>
 <unitpenalty>
  <text>0</text>
 </unitpenalty>
 <postunit>
  <text></text>
 </postunit>
 <ruleid>
  <text>1</text>
 </ruleid>
 <otherrule>
  <text></text>
 </otherrule>
 <autocomplete>
  <text>0</text>
 </autocomplete>
 <subqtext format="html">
<text><![CDATA[<p style="direction: ltr;">{a3}•10<sup>-{b3}</sup>=&nbsp; {_0}&nbsp; &nbsp; &nbsp;<br></p>]]></text>
 </subqtext>
 <feedback format="html">
<text></text>
 </feedback>
 <correctfeedback format="html">
<text></text>
 </correctfeedback>
 <partiallycorrectfeedback format="html">
<text></text>
 </partiallycorrectfeedback>
 <incorrectfeedback format="html">
<text></text>
 </incorrectfeedback>
</answers>
<answers>
 <partindex>
  <text>3</text>
 </partindex>
 <placeholder>
  <text>#D</text>
 </placeholder>
 <answermark>
  <text>1</text>
 </answermark>
 <answertype>
  <text>10</text>
 </answertype>
 <numbox>
  <text>1</text>
 </numbox>
 <vars1>
  <text></text>
 </vars1>
 <answer>
  <text>c4</text>
 </answer>
 <vars2>
  <text></text>
 </vars2>
 <correctness>
  <text><![CDATA[_relerr < 0.001]]></text>
 </correctness>
 <unitpenalty>
  <text>0</text>
 </unitpenalty>
 <postunit>
  <text></text>
 </postunit>
 <ruleid>
  <text>1</text>
 </ruleid>
 <otherrule>
  <text></text>
 </otherrule>
 <autocomplete>
  <text>0</text>
 </autocomplete>
 <subqtext format="html">
<text><![CDATA[<p style="direction: ltr;">{a4}•10<sup>-{b4}</sup>=&nbsp; {_0}&nbsp; &nbsp; &nbsp;<br></p>]]></text>
 </subqtext>
 <feedback format="html">
<text></text>
 </feedback>
 <correctfeedback format="html">
<text></text>
 </correctfeedback>
 <partiallycorrectfeedback format="html">
<text></text>
 </partiallycorrectfeedback>
 <incorrectfeedback format="html">
<text></text>
 </incorrectfeedback>
</answers>
    <hint format="html">
      <text>שימו לב לשגיאה ונסו שוב</text>
    </hint>
    <hint format="html">
      <text>שימו לב לשגיאה ונסו שוב</text>
    </hint>
  </question>

</quiz>