Calculated¶
Answer type: calculated
The student types a numeric answer: a number, or an arithmetic expression such as 3/4, 2^5 or sqrt(2)/2. It is graded by evaluating it to a number and comparing that with the value of $answer (relative tolerance 0.0015 unless you set one), so any arithmetically equivalent form is accepted.
No variables
$answer and the student's entry must both evaluate to a number. An
$answer such as "2*x + 3" cannot be evaluated, so every response,
including 2*x+3 itself, scores 0. For an answer that is an expression in
x, use Function (numfunc) with $variables = "x".
The minimum¶
Common Control:
$answer = "3/4"
3/4, 0.75, 6/8 and 1.5/2 all evaluate to 0.75 and are all accepted. Use this type whenever the form of the value is not what you are assessing; when it is, add $answerformat flags.
No [calculated] section, and no simplify option
Earlier versions of this page showed [calculated], answer = x^2 + 1;
and simplify = full;. None of it exists. The type is chosen in the editor,
options are plain $ variables, and there is no simplify option. To
require a simplified form, use $answerformat, for example "reducedfraction".
Options¶
| Variable | Effect |
|---|---|
$answer |
the correct expression — required |
$abstolerance / $reltolerance |
grading tolerance |
$reqdecimals |
grade to N decimal places: unless you set $abstolerance or $reltolerance, it sets $abstolerance to 0.5×10⁻ᴺ (2 → 0.005) and adds an "accurate to N decimal places" entry tip; the number of decimals typed is not checked |
$reqsigfigs |
required significant figures, enforced only when $answerformat includes decimal, scinot or scinotordec |
$requiretimes |
symbol-count rules the typed answer must satisfy, e.g. "^,=0" |
$requiretimeslistpart |
the same kind of rule, checked against each entry of a list answer separately |
$answerformat |
accepted-format flags |
$displayformat |
"point" wraps the input box in ( ), "vector" in < > |
$formatfeedbackon |
set to 1 to flag a correct value in the wrong format (it still scores 0) |
$ansprompt |
text before the input box |
$answerboxsize |
width of the input box |
$hidepreview |
hide the live preview |
$requiretimes¶
A quoted string of symbol, rule pairs checked against what the student typed; if a rule fails, the answer scores 0 even when its value is right. It does not change how the entry is read. To make students evaluate a power rather than copy it:
$answer = 32
$requiretimes = "^,=0"
32 and 16*2 are accepted; 2^5 has the right value but scores 0. A bare number such as $requiretimes = 1 is not a valid rule and is ignored.
$formatfeedbackon¶
A correct value in the wrong format, for example 0.75 where $answerformat = "reducedfraction" asked for 3/4, scores 0. Set $formatfeedbackon = 1 so the box is marked orange instead of red and the student can see that only the form was wrong, and state the required form in qtext.
Example¶
Common Control — setup:
$b, $d = diffrands(2, 9, 2)
$a = rand(1, $b - 1)
$c = rand(1, $d - 1)
$sum = makereducedfraction($a*$d + $c*$b, $b*$d)
Question Text:
<p>Add `$a/$b + $c/$d`. Write your answer in lowest terms.</p>
Common Control, continued — answer and options:
$answer = $sum
$answerformat = "reducedfraction,allowmixed"
$formatfeedbackon = 1
The sum in lowest terms scores full marks. An unreduced fraction or a decimal has the right value but the wrong form: it scores 0, and $formatfeedbackon marks the box orange instead of red so the student can see why.
See Also¶
- Number — when the student must type a plain number, not a calculation such as
3/4 - Function — when it is a function compared across a domain
- Math Entry — what students can type