Looking at Canvas's (old) quiz engine.
For a numerical question, you can set an "answer with precision": you give a decimal answer, and an integer precision.
It looks like "precision" means "significant figures", since 12.345 gets rounded down to 12.34.
But...
In reply to @christianp
Nobody told the person who made the front-end, because when I write 12.345 in the box it's immediately replaced by 12.3400, implying "precision" means "decimal places".
In reply to @christianp
The marking is also confusing. "12.34" is marked correct, as I expected, but so is "12.340", which doesn't represent the same precision.
While the QTI export's marking condition just says 12.335 < answer <= 12.345, that's not how Canvas marks it: "12.33888" is marked incorrect.
In reply to @christianp
This stuff isn't simple: @NclNumbas has a tonne of options for how to mark a single number (docs.numbas.org.uk/en/latest/ques…)
It feels like Canvas makes every mistake it can, resulting in contradicting at least one assumption anyone might make