For Japanese mathematics textbooks, giving answers to problems is not the absolute goal. Often times, they give instructions that encourage students to "explain" their own ideas about strategies for solving problems. What is more, sometimes there are instructions that require students to understand and compare others' explanations.
During actual math lessons, such explanation activities are carried out numerous times according to the textbooks. In the activities, teachers play the role of a facilitator that helps students to engage actively in discussions and to appropriately summarize what they have discussed.