Lesson 20 of Minna no Nihongo I focuses on helping beginners talk about shopping, purchases, and basic commercial interactions. This lesson emphasizes asking about products, inquiring prices politely, and using expressions for buying or choosing items. Learners are encouraged to practice vocabulary in context, combining nouns, verbs, and polite forms to create complete sentences suitable for daily shopping scenarios. Strategies include repetition, practicing dialogues in store settings, role-playing buying and selling situations, and integrating expressions into daily conversations, which strengthen comprehension and practical usage. Practicing Lesson 20 content allows learners to communicate effectively in shops, ask about products or prices, and make purchases politely, providing a strong foundation for handling common commercial interactions in Japanese.