There is a crisis of many years in Israel in the subject of mathematics learning. In the last PISA tests, conducted by the OECD during the last ten years, Israel is placed 39-41 among all the countries participated the research. It was also found that all the years Israel "won" to be one of the first three countries with the highest grade distribution among all the countries and economic entities participating in general and among OECD countries in particular. In addition, it was found that rate of Israeli students who fail the mathematics test is one of the highest in the organization countries. The goal of this research is comparing students' achievements in the Israeli education system and in the Finnish education system, which is considered a system with excellent achievements in mathematics and low-grade distribution rate in general and in mathematics grades in particular. This comparison is aimed to identify the Israeli education system's problems and learn the lessons to improve it. This article discusses the question what is the main success factor in mathematics in Israel compared to Finland according to the 2015 PISA test results and what can be learned from this difference? In this paper I have based on my research findings in which I analyzed the correlation between the PISA questionnaires and student achievement in mathematics. [This paper was presented at the TDID Doctoral Students' Conference, 14-16 May 2020.]