Calculated Question - Print view doesn't display anything

Hey Juan, I looked at this and this the PR as-is looks like a good start to me and I'm going to commit it.

I see what you mean about answer key, and refreshing the page will have a new random number generated each time as it is based on user input.

I agree that the answer key should have z={Formula} and not try to calculate it and this should be a new jira. Neither one makes sense right now.

I can open the new jira for you. Thanks for the patch!

The bug has been solved and now calculated questions are shown in HTML print view. It would be great if someone can review the PR, it solves the current problem described in the jira.

However, some doubts have arisen about the value which "Answer Key" should display. For example, in the Question:
Kevin has {x} apples. Jaen eats {y}. How many does Kevin have now? {{z}}

What would be the answer key?
+ In the HTML print view, with this PR, the answer key shows the real number for calculated values - i.e.: "6"
+ In the PDF print view the answer key shows the name of variables: "x, y, z"

We think that both are not entirely correct. The first one because each student would get a different value as an answer and the second one because there is no information at all just by showing all the variables.
In our opinion, the answer key should be something like z = {x} - {y}
If you agree, we would make a new jira to address this issue for both views.

Thanks

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Neither the calculated questions are not displayed when clicking the "Print HTML" button.

Images showing the question and the result of the print button