First grade students are learning addition with regrouping. Through the use of hands-on manipulatives including number lines, hundred charts, and base-ten blocks, students began developing a concrete understanding of adding multi-digit numbers. Working with pencil and paper, students are now writing number sentences vertically, adding the ones column first, carrying to the tens when needed, and solving the equation. In learning and practicing the process of addition with regrouping, students are asked to visualize and verbally explain the process to deepen their understanding.