Metacognition is the mind's ability to monitor and control itself or, in other words, the ability to know about our knowing (Dunlosky & Bjork, 2008). In mathematics education, the importance of the investigation of students' metacognition during their mathematical activity has been focused on the area of mathematics problem solving. This study investigates the spontaneous emergence of the metacognitive functions of control and monitoring, during the solving of different types of mathematical problems with fifth grade students. We used the "think aloud" method on a group of ten year old students and the results showed that metacognitive strategies were used by the students so as the metacognitive functions of control and monitoring to be achieved.