Addition Fact Fluency Activities | Missing Addends-Part-Part-Whole - Error Analysis Resource DescriptionMake practice to fluently add within 20 engaging, interactive, and meaningful with this CCSS-aligned digital activity! Perfect for Grades K–2, this resource helps students strengthen their understanding of part–part–whole relationships, practice missing addends, and build fluency with basic addition facts through fun drag-and-drop tasks, error analysis, and self-correction. What’s IncludedAct