I tried to report this bug to support chat but they insisted I report it as a new feature request because nobody believes it is a bug (sigh).
Create a classic quiz
Go to "questions"
Select " + New question"
Select "Numerical Answer" question tyupe
Enter some text like "test" in the question box
Click on the first "Exact Answer" dropdown
Change it to "Answer with precision"
Type a precision of "4"
THEN enter an answer of "10.2"
The answer should be shown as 1.020e+1 or 10.20 (if precision 4 means 4 significant digits)
OR the answer should be 10.2000 (if the precision 4 means 4 decimal places)
The answer is displayed as 10.1900
The FIRST bug is it seems to be running in to binary to decimal conversion issues so instead of 10.2, it is using 10.199999999999999...
It then SEEMS to properly limit that to four significant digits (so the 4 digits in 10.19)
But then a SECOND bug appears where for some reason, when the number is small enough that Canvas displays it without scientific notation, it is using the precision to show decimal places, not significant digits. So incorrectly displaying the incorrectly rounded four significant digits of 10.19 to an incorrect four decimal places, to give 10.1900.
Even if the rounding is considered correct, and the four decimal places are considered functioning as designed, then a slightly less incorrect answer should be 10.1999 not 10.1900
For the life of me I don't see why Canvas thinks fixing this has to be a "feature request" but since they insisted, here it is.