The document discusses different levels of understanding, including simple understanding and deep understanding. Deep understanding helps students internalize knowledge and use it in new ways, grasp relationships and make connections. It also discusses reasoning skills, which involve manipulating knowledge to interpret, infer, solve problems, make judgments. There are three aspects to reasoning: mental skills, declarative or procedural knowledge, and performing a required task. The document then examines six facets of understanding - explanation, interpretation, application, perspective, empathy, and self-knowledge - and provides assessment examples for each.