In this paper we discuss students' opportunities to learn to pose mathematical problems, based on a historical analysis of problem posing in the area of number and algebra in six series of Chinese primary school mathematics textbooks published since the 1950s. We examine changes in the proportion and distribution of the problem-posing tasks, and in the presentation of the problem-posing tasks. Our results show a decreasing number of problem-posing tasks as grade level increases, even though problem posing has become more important in mathematics education in China during the last 70 years. This study also provides a variety of examples of problem-posing tasks which could serve as a reference for teachers in other countries in designing and employing problem-posing tasks in the classroom.