This is a collection of our 3 digit addition with regrouping worksheets with answer keys. This is a good supplement to your lessons on adding numbers. You can use these math worksheets as a review, homework, quiz, pre test, drill, or practice for your students in the 2nd, 3rd, or 4th grades. *** View our Addition Bundle to save and get more activities.There are five sets in this product: Set 1: Aligned Vertical Addition (12 questions each) Set 2: Missing Addend, Show Solution Set 3: Fill in the