Purposes for Questions in the Classroom

1. Helping students work together to make sense of mathematics
2. Helping students to rely more on themselves to determine whether something is mathematically correct
3. Helping students to learn to reason mathematically
4. Helping students learn to conjecture, invent, and solve problems
5. Helping students to connect mathematics, its ideas, and its applications

(NCTM, Professional Standards for Teaching Mathematics, 1991, pp 3-4.)

The thing that stands out most for me is that every question is "helping students" to achieve some relevant goal. None of the examples have anything to do with the "answer" and none are "yes or no" questions.