The Ministry of Education and Training is actively promoting digital transformation, particularly the integration of artificial intelligence (AI) in general education. This shifts from traditional teaching methods to intelligent technologies and personalized learning. AI technologies such as Gemini support interactive learning environments by enabling simulation, visual representation, and personalized feedback, aligning well with active learning models, where students are encouraged to explore knowledge autonomously. Gemini’s application in teaching decimal numbers to 5th-grade students represents a convergence between pedagogical innovation and the adoption of advanced technological tools. This approach provides teachers with effective teaching aids, stimulates student interest, and contributes to the development of learner competencies. The study provides an overview of Gemini’s educational potential, identifies an effective prompt structure for Gemini, and proposes a process for applying the tool to design instructional scenarios. It also specifies Gemini applied in constructing real-life teaching situations for conceptualizing and operating with decimal numbers. A preliminary implementation was conducted with five lessons in Class 5A at the Pedagogical Practice School, affiliated with An Giang University. Initial findings indicate positive outcomes in contextualizing mathematical knowledge into real-life applications, diversify real-life elements, reducing over-reliance on textbook-based materials, and enhancing student engagement. This approach opens further opportunities for educators to expand the use of Gemini in designing other instructional content or to explore additional AI technologies that support teaching and learning activities, thereby contributing to improved educational quality.