Add info about rounding to Entry Tips

[githubapprentice]

This shows a rounding example in the Entry Tips and includes a message about decimal places or significant digits.

In some places the phrase "significant figures" is used. Although that's a standard term, I wonder if changing all of them to "significant digits" would be clearer to students who haven't been taught either phrase.

Due to problems with my development server, I wasn't able to test the short version of the Entry Tips and testing was limited in general.

Do I need to do anything about internationalization?

[drlippman]

Sorry I haven't done anything with this yet. I have a potentially conflicting accessibility change I might need to make first.

[drlippman]

So looking at this again, my concern is that saying "4 significant digits" isn't necessarily true, if the user has changed the $abstolerance or $reltolerance. I guess we could try to write a function to infer number of decimal values / sigfigs based on those, but I feel like sometimes I set those looser than what I tell students, which could lead to confusion.

I do like the idea of giving the example decimals as ones with 4 decimal places. I'll go ahead and make that change.

[githubapprentice]

I guess that might be the best we can do given that question writers may have more restrictive instructions in the question.

BTW, students sometimes see the Show Answer displayed with lots of digits and think they need to do that. What do you think about having the Show Answer display rounded according to $reltolerance, $reqdecimals and $abstolerance?

[edited after I re-read the previous comment more carefully]

[drlippman]

I'm a bit concerned that using $abs/reltolerance to auto-create entry tip rounding instructions might be problematic in some cases. As I mentioned, sometimes I set those looser than what I tell students, which could lead to confusion if they see conflicting rounding instructions. But maybe I'm the only one who does that :)

If we did, $reltolerance would probably lead to a "give your answer accurate to at least __ significant figures". $abstolerance should probably be "give your answer accurate to at least __ decimal places".

But what would $abstolerance = .005 translate to? Accurate to at least 2 places? 3?

[drlippman]

I daresay the right answer is probably that people should use $reqdecimals or $reqsigfigs instead of $abs/reltolerance, but obviously that doesn't help with all the existing questions.