In the project MultiMa (Multiple solutions for mathematics teaching oriented toward students' self-regulation), we investigated the effects of prompting students to use multiple solution methods while solving real-world problems on their learning. In this quasi-experimental study, we compared three treatment conditions. In one condition, students solved real-world problems by using multiple solution methods. These solution methods consisted of a solution using a table and a solution using differences. In the other two conditions, the same real-world problems were solved using only one of the methods. About 307 ninth graders from twelve middle track classes took part in this study during four lessons. Before and after a teaching unit, students' self-regulation was tested. [For the complete proceedings, see ED597799.]