This study proposes and evaluates an effective teaching method for non-technical adults who want to understand artificial intelligence (AI). As the number of non-technical business professionals who want to improve their participation in technical discussions is increasing, it becomes important to find effective teaching methods for non-technical adults who need to understand core technical concepts in which they are involved reasonably. The proposed teaching method utilizes the active use of visual feedback and agile practices to overcome the challenges the adult learners face. In this study, we evaluated the effectiveness of the proposed teaching method by the open coding method to analyze the free-form responses and by the paired t-test over the responses to the questions asked to the participants before and after the lecture. We found that this teaching method effectively supported the learners to understand the basic technical concepts of AI within one or two-day time frame. We also confirmed the non-technical adult learners had significantly changed their attitude toward understanding AI from initially negative to positive with a good expectation of success in understanding AI, which is one of the important outcomes for the learners as the expectancy-value theory predicts their future performance on understanding AI.