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Math Update and Fix

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On November 18, we deployed a change to math equation rendering around Canvas that caused chaos and pain for some math instructors using classic quizzes, namely in the form of breaking some math equations. Most of the problem was fixed by November 20, but we were resolving lingering issues with people’s ability to update broken equations through last weekend. This bug appeared at a particularly untimely moment, when many instructors were creating midterms or finals, which increased both the pressure and the complexity of the fix.

I apologize if you were affected by this bug. It was bad, it wasted a lot of time for a lot of people, and it shouldn’t have happened. If you want a detailed account of the confluence of things that went wrong and what we’ve learned, or if you want a personal apology, or if you want to vent to someone responsible for the problem, you can DM me or send me an email. I likely can’t fix the frustration we caused, but I can promise you that we care a lot, and that we’re applying the lessons we’ve learned to improve what we do and how we do it.

After reviewing every support case we received, it appears that many people have already fixed their own equations. This is good. If you’ve got a small number of equations that were impacted, manually updating them is the safest and fastest method of fixing them. If you’ve got a large number of equations that were impacted in a particular course, you can follow the instructions attached below to try an automated fix that we’ve created. There’s some risk that this automated fix won’t help your quiz, which is why we recommend manually updating where possible, or else first trying the automated fix on a copy of the impacted quiz.

From our testing, the automated fix improves 85% of the impacted quizzes. Due to the nature of the broken equations created by this bug, that success rate probably won’t improve, and we hope that the script we created is only relevant for a couple of weeks anyway. The success rate, the timing, the need for a quiz copy, and the proportion of people who have already fixed their own equations are the reasons we’re releasing this fix on-demand rather than automatically running it on all quizzes. 

If you run into any additional issues updating your quiz, please raise them to our support team or to your CSM, so we can investigate them quickly. At this time, we aren’t aware of any open issues with editing broken equations.




How do I run an automated data fix on a quiz with broken math equations?


  • If you’ve got a small number of broken equations, manually updating them is the safest and fastest method of fixing them.
  • From our testing, the automated fix outlined below improves 85% of impacted quizzes.
  • To avoid any risk of additional disruption, we strongly recommend running the automated fix on a copy of the impacted quiz before running it on the impacted quiz.
  • This fix doesn't impact existing submissions.

Create a copy of the impacted quiz. Note that the copied quiz will have the same name, so you may want to add it to a specific module during the copy process to ensure that you’re editing the copied version of the quiz in the following steps. Otherwise, if you know the original quiz ID, you can check the quiz ID in the URL to see which is the copy.


2. Enter editing mode on the copied quiz. The URL should look something like:




3. From editing mode on the copied quiz, add ?fixup_quiz_math_questions=1 to the end of the URL and press enter/return on your keyboard. The automated fix takes a couple of seconds to run.

The URL will look something like:




4. When the page reloads, review the changes to the quiz copy. Be sure to review the entire quiz.
5. If the changes look good, you can delete the quiz copy and repeat steps 2-5 on the original quiz, then save the changes. If the changes look bad or didn’t apply, the automated fix won’t work, and the affected quiz questions will need to be fixed manually.

The same ?fixup_quiz_math_questions=1 URL parameter can be run from quiz question banks. In that case, the URL will look something like:




Note that quiz question banks can’t be copied, so we recommend testing and reviewing the automated fix on the question bank of a copied course before applying the same fix to the original course.

Community Participant

This is not wholly related to what you are mentioning, but it is adjacent and will hopefully be fixed soon: The student view of new assignments with online submission breaks MathJax. Please see 
my post here.

Community Member

Please consider deploying updates in between semesters in the future. 


Community Member

The New Quizes engine does not have the capabilities of the old quizes engine as it is experimental. The old quizes engine is broken and not supported as the new quizzes engine is out. You are offering an experimental tool and a broken one and, as such, you end up offering only half of a product. This situation goes one for more than three years now.

I started using Canvas 3 years ago and the new engine was allready out. I had to switch to the old quizzes engine as critical functionality was missing from the new one (such as appropriate partial credit). The old quizes is broken and getting more broken every year. The new quizes is still not ready with critical functionality missing. At least during this challenging period, when we are struggling to support our students in difficult times, I would expect Canvas to invest on fixing these issues as soon as possible. At least I would expect the decency to test a change before releasing it. Instead of doing any of these Canvas chooses to further break the old engine while the new engine is still limited.

I have spent so many hours fixing what Canvas breaks that I feel Canvas ows me a paycheck. 

Feeling absolutely disrespected

Community Member


Recently equations are now showing properly when I preview quizzes. These questions are coming from a quiz bank and I an not sure what is happening. I gave the same quiz in fall 20 and it was fine. 


Any help would be appreciated.




Community Team
Community Team

HI, Kamal,

Have you submitted a support case? That's the best way to get help so they can do more triaging for you and see what may still be happening.



Community Member

Hi Erin,

I had to update each question in each bank. I changed the font size for equations to 12. I usually keep all font sizes to 14. However, I noticed that the new version makes equations much bigger than the text. I have used Latex when typing equations with \large to make them to match the font size of text previously. 

It worked for me and I already synced my Blue print master course with all the sections to use the same final exam. 




Community Member

I am noticing this keep happening even in pages and discussions when I use equations. 

Here is one of my reply to a student submission of a discussion post. 


It shows properly when editing :


To fix this keep only equation in a line. DO NOT keep both text and equations in one line.


Hope this is helpful for now.