Learning through Play is an educational approach that brings many advantages to teaching, especially math, but still faces many difficulties in approach and organization when applied in Vietnam. Meanwhile, the BOPPPS model - a model based on behavioral theory with 6 steps to help teachers be more oriented when building, connecting learning goals, and putting students at the center of the learning process, can be considered one of the effective measures and tools to help teachers apply Learning through Play effectively. Based on the theory of Learning through Play and the BOPPPS model, the paper proposes the teaching process approach Learning through Play according to the BOPPPS model in the content of the flat geometric area at the Primary level, thereby helping teachers better orient in building lectures and developing the necessary competencies for students.