Purpose: Written Think-Aloud strategy, which is rooted in the think-aloud strategy, gives students mental order and helps teachers explore thought processes; specifically, these methods are useful to study test response processes and map cognitive models of complex thought processes. The purpose of this research was to investigate the effect of Writing mathematical thoughts and arguments in non-mathematical and non-formulaic language improved elementary students' mathematical performance.
Method: The statistical population of the present study included the fifth-grade students of elementary school (n=60). The statistical sample was 32 students (control group (n=16) and experimental group (n=16)), who were selected by available sampling method. A pre-test-post-test design with a control group was used for the implementation of the present study.
Result: The results covariance analysis test indicated that the difference in the average scores of students in the control and experimental groups is significant (p≤ 0. 000). This research also indicated that the use of written think-aloud strategy in students' math assessment led to students' success in solving math problems.
Discussion and conclusion: This research showed that the use of the Written Think-Aloud strategy in the math assessment of students affected their math success. This success in solving math problems can be related to creating mental order and focusing more on the task and finally strengthening self-regulation skills, which is a necessary condition for achieving any kind of success. It also provides the basis for receiving quick and timely feedback improves the thinking process and leads to success in solving problems.