Why did the teacher assign extra homework when she taught adolescent riddle?

The teacher wants to add a lesson.

Homework is given to encourage students to master the lessons taught during the day. The students can review the concepts and practice answering questions regarding the lesson.

Homework can also be given for the students to study in advance for the next day's lesson to familiarize the concepts.

Most of the time, additional homework is given so that the students can develop the skill to independently learn and challenge own understanding.