<answer>

The following examples illustrate use of the <answer> tag attributes (Part 1).

Attributes

Attribute Examples

Example: disabled

  <p>Answer this to activate the next problem: 
    <answer name="ans1" symbolicEquality><label><m>2 - 1 = </m></label>1</answer></p>
  <p>Next problem: 
    <answer name="ans2" disabled="$ans1.creditAchieved != 1" symbolicEquality><label><m>$ans1.submittedResponse + 1 = </m></label>2</answer></p>

The condition within the disabled attribute is true until the user achieves credit for the first <answer>.

The symbolicEquality attribute was added to prevent mathematical operations in the answer validation, so that, for example, 2-1 is not a correct answer to the first question.

Example: weight

  <document name="assignment">
    <p>Question 1 (important)</p>
    <p>
    <answer weight="2" name="ans1"><label><m>1 + 1 = </m></label>2</answer></p>
 
    <p>Question 2 (less important)</p>
    <p>
    <answer name="ans2"><label><m>1 + 2 = </m></label>3</answer></p>
 
    <p>Credit for question 1: $ans1.creditAchieved</p>
    <p>Credit for question 2: $ans2.creditAchieved</p>
    <p>Total credit for assignment: $assignment.creditAchieved</p>
  </document>

This example illustrates the use the weight attribute within an <answer>. Use weight to reduce or enhance the proportion of total credit on the page obtained for a correct response to a
single <answer>. By default, each <answer> has an equal weight of $1$.

Example: inline

<p>The complementary color for red is 
  <answer inline>
    <shortDescription>complementary color for red</shortDescription>
    <choice>blue</choice>
    <choice credit="1">green</choice>
    <choice>yellow</choice>
  </answer>.
</p>
<p>
  <answer>
    <label>What is the complementary color for purple?</label>
    <choice>blue</choice>
    <choice>green</choice>
    <choice credit="1">yellow</choice>
  </answer>
</p>

For a multiple choice question, the inline attribute causes the choices to displayed using an inline format.

Example: handGraded

<p>
  <answer type="text" handGraded expanded>
    <label>In one sentence, describe the theme of the story</label>
  </answer>
</p>

The handGraded attribute is applied when auto-grading is not possible or preferred. The student’s responses are stored for future grading.

Example: matchPartial

When the matchPartial attribute is applied, an automated partial credit evaluation will be attempted, potentially giving credit between 0 and 1. Without the matchPartial attribute, the response must be completely correct before it receives credit.

The automated partial credit algorithm will attempt to break up logical conditions into pieces, look separately at components of vectors, and award partially matched choices.

More fine grained control can be obtained by adding multiple <award> children to an <answer> and giving each <award> a different credit attribute.

For comparison of vectors, the attributes matchByExactPositions and unorderedCompare influence the partial credit algorithm.

Example: symbolicEquality

<p>Your responses to these questions must exactly match our answers!</p>
<p>
  <answer symbolicEquality><label><m>2x + 5x = </m></label>7x</answer>
</p>
<p>
  <answer symbolicEquality><label><m>x^2 + 2x^2 + 3x + x</m></label>3x^2 + 4x</answer>
</p> 

Note that you cannot repeat the original expression in the first question, and you cannot commute the terms in the second question.

For answer validation that is more liberal (but still stricter than the default numerical checker), combine symbolicEquality with the simplifyOnCompare and expandOnCompare attributes.

Example: forceFullCheckWorkButton

<p>
  <answer><label><m>2x + 5x = </m></label>7x</answer>
</p>
<p>
  <answer forceFullCheckWorkButton><label><m>2x + 5x</m></label>7x</answer>
</p>  
<p>
  <answer forceFullCheckWorkButton submitLabel="check!"><label><m>2x + 5x</m></label>7x</answer>
</p>
<p>Move the below point to the first quadrant.
  <answer>
    <award><when>
      $P.x > 0 & $P.y>0
    </when></award>
  </answer>
</p>
<graph size="small">
  <shortDescription>graph for moving a point</shortDescription>
  <point name="P" />
</graph>

When an <answer> has an input field inside it, it will, by default use a small check work button to the right of the input field. To override this default and use the large button, add the forceFullCheckWorkButton attribute.

An answer without an input field uses the large button, by default. (See forceSmallCheckWorkButton, below).

With the large button, it is also possible to customize the message on the button using the submitLabel attribute.

Example: forceSmallCheckWorkButton

<p>Enter two numbers that add up to 5:
  <mathInput name="n1" forAnswer="$ans1"><shortDescription>first number</shortDescription></mathInput>
  <mathInput name="n2" forAnswer="$ans1"><shortDescription>second number</shortDescription></mathInput>
  <answer name="ans1">
    <shortDescription>two numbers that add up to 5</shortDescription>
    <award><when>$n1+$n2=5</when></award>
  </answer>
</p>
 
<p>Enter two numbers that multiply to 12:
  <mathInput name="m1" forAnswer="$ans2"><shortDescription>first number</shortDescription></mathInput>
  <mathInput name="m2" forAnswer="$ans2"><shortDescription>second number</shortDescription></mathInput>
  <answer name="ans2" forceSmallCheckWorkButton>
    <award><when>$m1 $m2=12</when></award>
  </answer>
</p>
 
<p><answer><label>1+1=</label>2</answer></p>
 

When an <answer> does not have an input field inside it, it will, by default use a full check work button. To override this default and use the small button, add the forceSmallCheckWorkButton attribute.

An answer with an input field always uses the small button, by default. (See forceFullCheckWorkButton, above.)

If both forceFullCheckWorkButton and forceSmallCheckWorkButton are supplied, forceFullCheckWorkButton takes precedence.

Example: simplifyOnCompare

Specifying the symbolicEquality attribute switches to a symbolic answer-checker that demands exact syntatical equality. The symbolic equality can be relaxed with the simplifyOnCompare attribute.

The simplifyOnCompare attribute has five options:

• simplifyOnCompare="none": the default value of demanding exact equality.
• simplifyOnCompare="full" (or simply simplifyOnCompare by itself): apply currently available simplification routines before checking. Does not include expanding factored expressions.
• simplifyOnCompare="numbers": simplify numerical expressions like 1+2 but not algebraic expressions. Permute terms and factors into a canonical order before checking equality.
• simplifyOnCompare="numbersPreserveOrder": simplify numbers but without permuting terms or factors.
• simplifyOnCompare="normalizeOrder": permute terms and factors to a standard order but perform no other simplifications.

To include expansion of factored expressions, you can add the expandOnCompare attribute.

Note: if symbolicEquality is not specified, simplifyOnCompare has no effect.

Example: expandOnCompare

The default comparison is a numerical answer-checker with a liberal definition of equality.
Specifying the symbolicEquality attribute switches to a symbolic answer-checker that demands exact syntactical equality. The symbolic equality can be relaxed with the simplifyOnCompare attribute. To expand factor expressions prior to comparison, you should also include the expandOnCompare attribute.

Note: if symbolicEquality is not specified, expandOnCompare has no effect.

Example: unorderedCompare

<p>
  <answer>
    <label>Enter <m>1,2,3,4,5</m></label>
    <mathList>1 2 3 4 5</mathList>
  </answer></p>
 
<p>
  <answer unorderedCompare>
    <label>Now enter <m>1,2,3,4,5</m>, but scramble the order up</label>
    <mathList>1 2 3 4 5</mathList>
  </answer></p>
 
<p>
  <answer>
    <label>Again, enter <m>1,2,3,4,5</m>, but scramble the order up</label>
    <mathList unordered>1 2 3 4 5</mathList>
  </answer></p>

When multiple values are compared within a single <answer> tag, the default behavior is to match the order of the sequenced values. If order is irrelevant, use the unorderedCompare attribute.

unorderedCompare can be used with list components (e.g., <mathList>, <numberList>, and <textList>) as well as the <math> component containing a list (e.g, $1,2,3$), tuple (e.g., $(1,2,3)$) or array (e.g., $[1,2,3]$).

Alternatively, and for more control over what is ordered, one can add the unordered attribute directly to a list component or a <math>, which will cause an unordered comparison to be used when comparing it to anything else.

Example: matchByExactPositions

<answer matchPartial matchByExactPositions>
  <label>Earn partial credit by getting some of the components of <m>(1,2,3,4)</m> correct</label>
  (1,2,3,4)
</answer>
 
<p><answer matchPartial>
  <label>Earn partial credit by getting some of the numbers <m>1,2,3,4</m> entered in order</label>
  1,2,3,4
</answer></p>

The attribute matchByExactPositions influences how the matchPartial calculates partial credit involving vectors, lists, and related quantities. Without matchByExactPositions, the vectors $(3,1,2)$ and $(1,2,3)$ would be deemed by matchPartial to have a 67% match, as both contain the sequence $1,2$, even though no components match. With matchByExactPositions, they would have a 0% match, as none of the first, second or third coordinates match.

In general, for a comparison of vectors, one would want to include matchByExactPositions along with matchPartial to give partial credit only for matches in a coordinate. For comparing ordered lists, matchByExactPositions may not be desired.

matchByExactPositions implies an ordered comparison, so attributes like unorderedCompare and unordered are ignored.

Example: numAwardsCredited

<p>
<answer numAwardsCredited="2">
  <mathInput name="userNumber"><label>Enter an even number greater than 6</label></mathInput>
  <award credit="0.5"><when>
    $userNumber > 6
  </when></award>
  <award credit="0.5"><when>
    <mod>$userNumber 2</mod> = 0
  </when></award>
</answer>
</p>

By default, if an <answer> has multiple <award> children, only a single award will be credited. If multiple awards match, then the award with the largest credit will be chosen (with order in the document breaking ties).

The behavior can be changed by setting the numAwardsCredited attribute to an integer larger than the default of 1. If numAwardsCredited="2", then up to two <award>s can be matched, and the credit achieved will the sum of their corresponding credits (up to a maximum of 1).

Combining multiple <award>s with numAwardsCredited can be an approach for assigning partial credit based on different required aspects of the answer.