What is the best way for a teacher to assess a third grade student's understanding of a problem solved correctly?

Asking the student to explain the steps they took to solve a problem gives insight into their understanding and thought processes. This method encourages students to verbalize their reasoning, which can reveal whether they grasp the underlying concepts or are simply producing correct answers without comprehension.

When students articulate their problem-solving steps, it allows teachers to identify any misconceptions or gaps in knowledge. It fosters a deeper understanding of the material and promotes critical thinking skills. This approach also provides an opportunity for the teacher to guide the student if there are errors in their reasoning.

Other options, while potentially useful in certain contexts, do not provide as comprehensive an assessment of understanding. Checking only the final answer does not account for the student's reasoning process. Giving a similar problem may show if they can replicate success but won’t clarify their understanding of the concepts behind the problem. Providing feedback on written work is important, but it is often most effective when it follows an understanding of how the student approached the problem in the first place. Thus, asking the student to explain their steps is the most effective method for assessing their understanding.