In this article in Mathematics Teacher, Nicora Placa (Hunter College) remembers, as a new teacher, looking over a student’s shoulder and spotting this problem: 1/3 + 1/4 = 2/7 Here was the ensuing conversation:
- Teacher: I see you added the numerators and denominators. Are those the same size pieces?
- Student: Yes?
- Teacher: Are you sure those pieces are the same size?
- Student: Um. No?
- Teacher: Good! So, what do we do if they aren’t the same size?
- Student: Um…
- Teacher: I’ll give you a hint. We worked on it yesterday. We need to find…
- Student: The same size?
- Teacher: Yes. We need to find common…
- Student: Ummmmmm… denominators?
- Teacher: Yes. Very good! We need to find common denominators. Why don’t you review the notes from yesterday on how to find the common denominator and then redo this?
“I did this with the best of intentions,” says Placa, “thinking I was helping the student. I truly believed that with some prompting or a hint, they would remember what to do. I did not understand that I was dragging them through a solution path that made sense to me instead of trying to understand how they were thinking about the task… I was not hearing all the interesting ways students thought about the problem, and I misunderstood their ideas.”
A little later in her career, Placa learned the value of student interviews and began to approach conversations with students in a different way – even when their answers were correct. “When conducting these interviews, I began listening to students with the goal of making sense of what they were doing,” she says. “It was eye-opening. I was able to learn about the different strategies that students brought to the problem and, in turn, change my responses in the classroom… I became fascinated by all the ways students thought about problems and started to build on these conceptions to design instruction.”
Using this approach, here’s how Placa would handle the conversation with a student who had written this incorrect solution: 1/3 + 1/4 = 2/7
- Teacher: Can you tell me how you got your answer?
- Student: Is it wrong?
- Teacher: I don’t know. Why don’t you explain it to me, and we will try to figure it out together?
- Student: Well, here you have one of three things, and here you are adding one out of four things, so basically you now have two of seven things.
- Teacher: Interesting. Can you try using these manipulatives or a drawing to show me another way to solve it?
“With this change in questioning,” says Placa, “I could see how this solution made sense to students if they thought of a fraction as two distinct whole numbers and not as a quantity itself. Listening to students’ thinking made me rethink the ‘out of’ fractions language I was using when introducing fractions and whether I was sufficiently allowing students to explore a variety of models. I revisited activities that explored the concept of fractions as a quantity before I tried to address the addition of fractions.”
When she became a math coach, Placa became an advocate of student interviews, and Let’s ask a kid! became her mantra. She encourages teachers to anticipate different ways students might solve challenging problems, interview individual students outside of regular class time, and choose effective questions to probe kids about their solutions. She counsels teachers to avoid responses like:
- That’s right!
- You know that if you just…
- Remember what we did in class last week…
- And --- is just another way to say ---.
- Do you mean…?
Instead, she helps teachers use interview questions like these:
- General probing questions:
- What did you notice?
- Why did you write (or draw) that?
- You wrote ---. Why? How did that help you?
- I noticed that you stopped what you were doing just now (or erased or crossed something out). What were you thinking?
- I don’t know what you mean by that. Can you explain?
- Questions about alternative solution paths:
- Can you solve it in a different way? Tell me about it.
- Can you use a picture (or tool) to represent your thinking? Show me.
- Another student said the solution was ---. Do you agree or disagree? Why?
- Questions about explaining and justifying solutions:
- How do you know?
- How did you figure that out?
- How sure are you of your answer? Why?
- Can you justify your work with these manipulatives?
- Is there another way to justify your work? What is it?
- What did you notice about the student’s thinking?
- In what ways do the student’s explanations make sense?
- What different conceptions do you notice the student has?
- What types of questions help uncover the student’s thinking?
- What questions are less helpful?
- What instructional moves might be helpful if we notice these ideas in our classrooms?
- What implications does this have as we plan instruction going forward?
“Let’s Ask a Kid! Conducting Student Interviews” by Nicora Placa in Mathematics Teacher: Learning & Teaching PK-12, December 2024 (Vol. 117, #12, pp. 900-906); Placa can be reached at np798@hunter.cuny.edu.
Please Note: This summary is reprinted with permission from issue #1067 of The Marshall Memo, an excellent resource for educators.