Product Description3-Digit Addition Worksheets for 1st, 2nd, and 3rd Grade | 20 Pages, 400 Problems Build accuracy, confidence, and place-value understanding with this comprehensive set of 3-digit addition worksheets. Designed for grades 1–3, this packet provides abundant practice to help students master adding within 400, develop regrouping skills, and strengthen fluency with the standard algorithm. Across 20 printable pages and 400 total problems (about 20 per page), students get clear, unclut