It may be a useful self assessment activity to think about how you question your pupils.

How long do most of your interactions with pupils last? A few seconds perhaps - like a game of 'ping pong'?

Is there anything wrong with having so many short interactions? What can be done to make them more rich (long and deep)?

Pupils can be asked to explain their answer. But this can still lead to a ping-pong closed interchange between teacher and individual pupils, with negative impact on  classroom dynamics - few contributing; many disengaging.

By contrast, the 'volleyball' approach is where an answer from one pupil is 'opened up' to provide a rich, deep class-wide discussion. This encourages all pupils to think about each question posed by the teacher i.e universal, continuous engagement.

(An alternative model is to get the pupils to pose the questions i.e. "Ask me a question which would test whether I have understood X")

For example, in the "teacher-asks-the-questions model, the teacher might ask “What is the next number in this sequence?”

Pupil 1 may give a correct answer with reason (e.g. "Add 4").

Rather than just saying "Correct" (which closes the interaction), the teacher could ask the rest of the class if they agree, and if they can improve on the reason. (This keeps the interaction open and allows it to get richer.)

Pupil 2 may agree and say “We add 4 to the last number, to get the next number in the sequence.”

Pupil 3 may offer “We add 4 to the previous term to get the next term in the sequence.”

We can clearly see an improvement in the reasons given, leading to a better understanding and more developed mathematical language. The message is: the sum of the whole is more than the sum of the parts.