In this study, a spreadsheet-based visualized Mindtool was developed for improving students' learning performance when finding relationships between numerical variables by engaging them in reasoning and decision-making activities. To evaluate the effectiveness of the proposed approach, an experiment was conducted on the "phenomena of climate on earth" unit of an elementary school geography course. The experimental results showed that the spreadsheet-based visualized Mindtool significantly benefited the students in terms of improving their learning achievement and promoting their learning attitudes and satisfaction. Moreover, the cognitive load of the students was significantly decreased, indicating the effectiveness of this approach in helping students comprehend, learn content and organize their knowledge. To further investigate the learning behaviors of high-achievement and low-achievement students in using the spreadsheet-based Mindtool, a learning pattern analysis was conducted by coding the students' behaviors recorded on video.