This study focuses on developing and evaluating a computer aided learning environment that will enhance students' ability in cogitation, hypothesizing, verification, and problem solving. The design of such computer aided learning system is based on the combination of Jonassen's (1996) Mindtools concept, Ausubel's subsumption theory and Network multimedia peculiarity in order to construct a curriculum-orientated computer visual simulated learning environment. Such simulated environment provides advanced organizers for students to associate existing knowledge to new coming concepts. This computer aided learning system employs spreadsheets and visualized tools as Mindtools for active exploration, cognition, and problem solving of learners. In addition, it organizes reference models for teachers and students in order to perform meaningful learning. To estimate benefit of this visual simulated learning environment, the study adopts Quasi-experiment. 105 students of 6th-grade elementary school classes were surveyed. The development of this visual simulated learning environment is to pursue an applicable teaching method with the students as the main body and the computer as Mindtools. It helps the learner to develop the concepts of probability through the steps of experiencing, realizing and understanding.