Can you get more concrete about what you mean when you say, in your mistakes section, "Teachers struggle to get students’ math ideas"? This might help make your fixable root cause more specific.
Your exisiting solutions are interesting – "Teachers try to get students’ ideas by asking some leading questions, which might not fully represent students’ own thinking" and "Teachers might be provided with a list of productive questions they can ask during math discussions before teaching" – although they are broad. This week, it will be useful for you to try and see how the literature is speaking to these two solutions in more detail. It might help you figure out how to make your research questions contribute to the conversation in a more meaningful way. As they stand right now, it seems like you are going to be asking questions that are similar to those that have already been asked and answered.
Think about what's changed when you shift your question from "how can teachers" to "how DO teachers" ask productive questions. Again, I'm not intimately familiar with the literature you are citing, but this shift from "can" to "do" might be a useful way for you to think about how teachers take up these practices and implement them in the moment. Talk to Miriam Sherin!
- Research venue to be changed to a particular journal v location
- Update the stakeholder (e.g., who is going to be most interested in your proposal). Perhaps a principal? A district? The district may be too broad, but I do not think the stakeholder will be the math teachers.
- I think for task/learner you may need to narrow down or rather clarify the learning task at hand v instructional activity
- For the "fixable root cause," I would suggest steering away from the age of the learners as the problem because it is not fixable. I think you will also want to be more specific regarding translating a "situation or context" into mathematically understanding. Try to identify a cause of the problem v the mistake the students are making.
- The research question focuses on instruction, but instruction wasn't previously mentioned. Add in your focus on instruction into you canvas earlier.
I'm really interested in how your question develops!
Stakeholder: Teachers are the implementers of your research, they aren't the stakeholders. Who feels the urgency of the problem you're describing? Who is calling the shots? A school district? School leader? A specific curriculum developer? Government school funders?
Learner: Do you want to narrow this more? To a specific location or demographic?
Learner Task: I think you need to narrow the focus a bit- is your goal for students to be able to use a ten-frame? Or explain their thinking about a ten-frame? Or see how 10 breaks down into multiple components? All of those could be valid.
Learner mistakes: Again- I think you need to focus in on one of your two suggestions. Are you suggesting that students aren't able to communicate their thinking? Or that students don't have the strategy tool-kit to do the thinking in the first place? Those lead to two very different options.
At large, I think you need to decide if you want to focus on the communication element of math ideas or on the development of the math ideas themselves. Maybe think about which of those two areas has less work done on them already? Your research question would need to be adjusted based on that choice.