Early elementary school students are expected to solve twelve distinct types of word problems. A math researcher and two teachers pose a structure for thinking about one problem type that has not been studied as closely as the other eleven. In this article, the authors share some of their discoveries with regard to the variety of both-addends-unknown problems and offer suggestions for classroom practice when creating and implementing these types of problems. The authors intended that the analytical structure posed in this article will initiate discussions about important considerations with regard to using both-addends-unknown problems in instruction and assessment. They offer a recommendation that teachers, curriculum developers, and assessment-item writers carefully consider the thoughts and experiences shared in this article when selecting or writing both-addend-unknown problems to pose to students. Finally, the authors encourage careful consideration of number choice, the type of problem (attribute, placement, or model dependent), the inclusion of zero, and how manipulatives will be used in administering the problem. Such careful implementation will offer crucial insight into how students interact with the mathematical ideas inherent in these problems.