Which component most reliably characterizes explicit and systematic instruction in mathematics?

• A. The teacher models several different examples of adding fractions with the student. The teacher then encourages a student to think aloud while adding simple fractions. The teacher provides the student with corrective feedback throughout the activity.
• B. The student works alone after teacher demonstrates once.
• C. The teacher provides only a list of rules to memorize and assigns many problems.
• D. The teacher uses only discovery-based activities with no modeling.

Answer: (A)

Explicit and systematic instruction in mathematics uses clear modeling of the steps, makes the thinking process visible (often through a think-aloud), and provides ongoing corrective feedback during guided practice. This combo—demonstrating multiple examples, verbalizing the reasoning as students observe, and giving corrective feedback throughout the practice—embodies a structured, teacher-led approach that helps students learn the procedure and underlying concepts with support.

The described scenario fits this approach: the teacher shows several examples, verbalizes the reasoning while solving, and offers feedback all along. That combination is exactly what makes instruction explicit and systematic. The other patterns miss key elements: one-time demonstration without guided practice and feedback, relying on memorization of rules, or relying solely on discovery without modeling or feedback.