Because previous research has indicated a highly positive relationship between problem solving and posing, the process of problem solving can be adopted to design materials for problem posing. In this vein, the purpose of this study is to design a learning system for problem posing by annotated expressions through adoption-based research, in particular, a content-first design approach. More specifically, this study, inspired by solution trees, first designs annotated expressions for problem posing as content samples. In order to assess the effect on the assessment goal of problem-solving abilities, this study conducts an experiment, whose results show that problem posing by annotated expression may improve students’ performance on problem translation and two-step problem formulation abilities more than problem posing by pure expressions. Accordingly, this study then designs a computer-based learning activity to support and sustain such a method for problem posing. Finally, a classroom adoption, conducted in an authentic classroom, may suggest a positive outcome and future research on designing computer-based problem posing.