In this study, the effectiveness of a learning management plan using the think-pair-share technique on students' learning of decimal multiplication and division was investigated. The quasi-experimental study involved 42 grade 7 students in a public school in Thailand, who were simple random sampling. The study used a learning management plan, a learning achievement test, and a scoring rubric as instruments and employed the effectiveness index and a paired samples t-test to analyze the results. The results showed that the think-pair-share technique was effective in improving the student's understanding of decimal multiplication and division and that the students demonstrated learning outcomes on most topics and met the requirements on the post-test. The study also found that there was a significant improvement in the student's scores on the pre-test and post-test.