This study examined the influence of addition and subtraction practice embedded within a word-problem intervention for Grade 3 students experiencing word-problem difficulty. Students (N = 448) were randomly assigned to one of two variants of a word-problem intervention or a business-as-usual comparison condition. Within the word-problem interventions, students participated in targeted addition and subtraction fact and computation practice for approximately 3 minutes of each 30-minute session across 47 intervention sessions, but also continually practiced addition and subtraction through word-problem solving. At posttest, students who participated in the intervention demonstrated improved single-digit addition and subtraction performance as well as improved double-digit addition and subtraction performance. At follow-up in Grade 4, persistence of effects was only identified for double-digit addition. Considering addition and subtraction are foundational to many other mathematics skills, addition and subtraction practice serves as an important component of mathematics intervention.