While addition and subtraction is a key mathematical skill for young children, a typical activity for them in classrooms involves doing repetitive arithmetic calculation exercises. In this study, we explore a collaborative way for students to learn these skills in a technology-enabled way with wireless computers. Two classes, comprising a total of 52 students in Grade 4 (ages 10 or 11) participated in the study. They used the Group Scribbles software to run an adapted version of the "Cross Number Puzzle" that was designed with the "feedback" mechanism to assist students' problem solving. In one class, students played the game individually and in the other class, students played the game collaboratively. The low-ability students in the collaborative class were found to have made the most significant progress in arithmetic skills through playing this game. Three dominant interactive collaboration patterns, one contributing to productive interactions and two to less productive interactions, were also identified in the students' collaboration. (Contains 8 tables and 22 figures.)