This document provides guidance for teachers on developing deep-thinking mathematical questions for elementary students. It explains that open-ended questions that require analysis, criticism, and justification promote higher-order thinking skills. The document recommends using a "backwards by design" approach of first identifying a topic, then writing a closed question with an expected answer, and finally developing another question that addresses the expected answer. Teachers are encouraged to practice this process so they can more easily create good questions that develop deep conceptual understanding rather than having just one right answer.