cellDisableEvaluation for newly added table cells

I have been revising this lovely Open Middle rational number computation challenge:
[Rational Number Computation (7.NS.1 7.NS.2) • Activity Builder by Desmos]
and I am wondering a few things–

  1. Is there a way to make column headings images instead of text (I added letters to the different parts of the expression but was looking for something slightly more elegant)
  2. If a student wanted to add more rows to the table, how could I disable cell evaluation for those additional rows? Right now, I have limited them to 5 attempts, but I could see some students trying more than that to be certain that they have found the expression with the greatest or least absolute value.


I don’t think there is a way to do that. You could make the table a lot bigger and add code to disable evaluation, and initially have the maxRows set to say 5, and if they click a “more” button, increase the maxRows to show the rest of the table.

FYI, if you like to use open middle problems, it’s really helpful to learn how this template works. CL Newsletter October 2020: Open Middle • Activity Builder by Desmos

I can help edit this to your particular problem if you like.

What are all of the empty boxes for? And what “problem” are you talking about?

I would love that! I am slowly starting to understand more of what is going on the graph space, but I grew up before graphing calculators were a thing and I was not a math major, so it is a steep uphill climb for me!

The problem is the one in the linked activity (Rational number computation). I wanted students to be able to record the equations they had tried in a table, but work out the solution without the cells doing the calculations for them. Some students will stop after one or two tries, but others will keep going. The CL that disables cell evaluation is applied cell by cell ahead of time and I was wondering if there was a way to write the code so that any cells added by students would have cell evaluation already disabled.

You can accomplish this by setting that column to “Format as Text” as this does not evaluate cell contents by default.

No problem. Here it is: open middle - rational number computation • Activity Builder by Desmos

I made it so that it would automatically enter the expression into a table if the student enters the correct value of the expression. It will hold up to 15 expressions (you can add more if desired, you would just need to copy/paste the code for each). It also displays the best answer they achieved so far.

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That is true, but then it is much harder to type equations.

That is beautiful! Thank you!

But your activity calls for numeric values does it not? If it’s an equation there’s no expression to evaluate.

For your use-case this works. Use what you like though