This study is an action research that focuses on written communication in problem solving. A cheat sheet has been created as a tool and aims to support the pupils while working with problem solving. The study began with a pre-test, continued with detail lesson plans included the cheat sheet. The study ended with a post-test where the pupils had access to the cheat sheet. Pre- and post-test have been analyzed based on two different frameworks, which focus on content and functions, as well as quality in pupil solutions. The result has been shown to be positive and pupils have improved their ability to write answers, report all the steps and keep a good layout. The cheat sheet could therefore functions as a suitable tool in the problem-solving process.