The present study compared Turkish and Singaporean textbooks with respect to their instructional contents on a difficult topic for most students: the concept of angle. The study used the 3rd and 4th grade mathematics textbooks taught in Turkish and Singaporean schools. The analysis showed that Turkish textbooks defined the angle as a static concept, and Singaporean textbooks defined it as both a static and dynamic concept. The definitions of the concept of angle included in the textbooks reflect on the representation of the angle, instructional tools and problems. Turkish students learn angle from textbooks only as a static concept, so they may have difficulties and misconceptions about the subject and related concepts. The findings showed that the contents of Singaporean textbooks offer students more opportunities than Turkish textbooks in learning about the angle as a static and dynamic concept.