Addition With Regrouping Worksheets for 2nd Graders Add 3-Digit and 1-Digit Numbers with Regrouping: Vertical Addition Every 2nd graders needs this worksheet to master add within 1000 with regrouping. Aid your child on their learning journey as they practice with regroup ones and add. 2 3 Regroup ones and add Add 3-Digit and 1-Digit Numbers with Regrouping: Missing Digits