First grade students are learning addition and subtraction 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 and subtracting multi-digit numbers.  Working with pencil and paper, students are now writing number sentences vertically, starting at the ones column first, carrying to the tens or borrowing from the tens when needed, and solving the equation.  In learning and practicing addition and subtraction with regrouping, students are asked to visualize and verbally explain the process to deepen their understanding.