Feedback when powers are not simplified

Hello! I’m still new to CL and don’t really understand the coding. I usually find some coding and copy and adjust to what I need.

I am currently working with my 8th graders on simplifying expressions involving powers. We are working on Powers of a Product and want to provide feedback when they have not quite simplified their power.
Here is the problem I am working on.

If they type 2^6*2^8, I want to provide them with feedback such as “Your expression is still not simplified; Try using the Multiplication of Powers property to simplify your expression.”
Or, if they type (2^7)^2, I’d like to provide them with feedback such as “Your expression is not simplified; try using the Power of a Power Property to simplify your expression”

That is, both answers are technically not incorrect, but rather not simplified and I want to provide them with specific feedback, depending on what they enter.

Hi Isabel! Try this out and see if it works as desired:

Giving feedback based on the format of a student’s answer can require complicated CL code, often using the patterns library. The Desmos team put together a whole YouTube playlist about the patterns library, if you want to know more.

For your activity, I used the patterns library and a check on the numeric value of the student’s expression to determine what feedback to provide. I made two small additions on top of what you requested:

  • If they enter another value that is correct but not in the desired format (e.g. they type in 16384), there’s a reminder to write their answer as an exponent using the base from the original expression
  • I turned off the auto-evaluation in the answer box so that the numeric value of whatever they type in does not automatically appear

I’m happy to explain in more detail how the code works, if you want. I hope this helps!

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Here is a version that includes some of the feedback you were interested in. Note you do need to use patterns.

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