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## Precision and exponents in quiz

I see that we can now use exponential notation like 6.3e12 in numerical quiz answers, and that's a really good thing.

I am not at all clear about the precision setting.  The release notes and user guide wasn't much help, and some examples would be useful.  It looks like I will need to set a precision of something like 12 if my numerical answers are small, as in the e-11 range.  Or at least that's what seemed to be working today.  If that works, great.

My real question is about setting margins or ranges.  I usually need a +/-2% to +/-5% range for calculated physics answers to accommodate internal rounding.  I don't see that I can set a range for those small numbers when I have Precision turned on.  So my correct answer might be 6.4e-12 +/-5% or +/- 3.2e-13.  This is really important.  Am I missing something?

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Community Champion

Hi John,

I've been working on some example problems that might help you, but I've found a problem that is going to prevent you from using formula based problems with answers that are smaller than .0001 (or require more than 4 places after the decimal point).

A typical physics problem might be to calculate the wavelength of light with a frequency of 7.26e14 Hz.

If you wanted to use a formula question in a Canvas quiz you could define the frequency as a variable. In the example below I did so, but you'll see the problem is that Canvas only allows 4 decimal places in their formula engine, and it computes the answer as zero rather as shown below.

So you can see in this example any answer that is +/- 5% from zero will be marked correct rather than what I intended which would be something like +/- 5% from 4.13e-7 (which would depend on the value of f used).

So for now, I think your best bet on these types of questions would be to use multiple choice or change units in the givens or answer so that your dealing with larger numbers.

I'm reporting this as a problem to technical support (case# 01172996), but it may be a limitation of the current quiz engine, and may need to be addressed in the development of the Modern Quizzing Engine​. Either way, I'll report back what tech support sends me so you'll know what to expect in terms of a better solution.

If you have any further questions, please keep them coming

10 Replies
Community Team

@john_bowen ​, it looks like you've stumped the community with this question! I'm adding this comment so that the question gets "bumped" and thus, I hope, will attract new sets of eyeballs.

Community Coach

I'm not sure of the answer to this, but I'm going to share it with the Teaching Math in Canvas​ group! Hopefully they'll be able to help out!

Community Participant

That would be great.  I would really like to use neg. exponent answers with a specified ranges.

Community Champion

Hi John,

I've been working on some example problems that might help you, but I've found a problem that is going to prevent you from using formula based problems with answers that are smaller than .0001 (or require more than 4 places after the decimal point).

A typical physics problem might be to calculate the wavelength of light with a frequency of 7.26e14 Hz.

If you wanted to use a formula question in a Canvas quiz you could define the frequency as a variable. In the example below I did so, but you'll see the problem is that Canvas only allows 4 decimal places in their formula engine, and it computes the answer as zero rather as shown below.

So you can see in this example any answer that is +/- 5% from zero will be marked correct rather than what I intended which would be something like +/- 5% from 4.13e-7 (which would depend on the value of f used).

So for now, I think your best bet on these types of questions would be to use multiple choice or change units in the givens or answer so that your dealing with larger numbers.

I'm reporting this as a problem to technical support (case# 01172996), but it may be a limitation of the current quiz engine, and may need to be addressed in the development of the Modern Quizzing Engine​. Either way, I'll report back what tech support sends me so you'll know what to expect in terms of a better solution.

If you have any further questions, please keep them coming

Community Champion

Just to follow up, here is the response I received from my support ticket:

Thank you for contacting Canvas Support and thank you for participating in our Community. Your screenshots was very helpful. At the moment small numbers in quiz formula does work as intended. I do recommend creating a feature request. We appreciate getting feedback as we are strive to improve Canvas. You may create a feature request here.

So the answer is Canvas was not designed to handle formula problems which would require more than 4 decimal places of precision to resolve correctly. To be fair, this is a pretty specific use case, but I think it warrants at least a new Canvas Feature Ideas​ submission. If you decide that is something you want to pursue, please post a link to your feature request here for so that anyone who finds this thread will know about it and have a quick way to vote and comment on your idea.

You've got my vote!

Community Participant

Thanks, @Chris Long.  You are seeing what we see, that its a limitation on those small numbers in both formula and numerical questions.  Our workaround last year was as you suggest:  Provide the exponent or the prefix needed (e.g. "Answer in nN or ___ x 10-9 N).  At least we can ask students for a reasonable significand, and that's still better than multiple choice.

I was hoping the new exponent system had a feature I was overlooking, and I guess we will just keep on with that limitation for small numbers.  At least we have options for the larger exponents now.  I hope the Modern Quizzing Engine will address this.

John

Community Champion

Thanks for confirming this John. I tried every possible trick I could think of with the numerical answers this morning but the limit for precision is 4 decimal places there as well :smileyconfused: so for now the workarounds are the only way to make this work.

Community Member

I would also like to use this feature in Chemistry with calculations using avagadro's number.  The answers will be in scientific notation with large numbers.  Please fix this problem in Canvas

Community Participant

Not permitting variables to represent values with more than 2 digits after the decimal point and not permitting the value of a variable to be represented in exponential notation is simply brain damaged. Come on Canvas, try to think outside the very limited box you are trapped in when designing the software. This is just one more frustrating thing that Canvas cannot do but other, better LMS's can, but unfortunately, I am forced to use Canvas. Sigh.