Math Monsters ~ Addition & Subtraction With Regrouping Color By The Code Puzzles . Math Monsters ~ Double Digit Addition And Subtraction With Regrouping Color By The Code Puzzle Printables. ~This Unit Is Aligned To The CCSS. Each Page Has The Specific CCSS Listed.~ This set includes 8 math puzzles- 2-Digit Addition & Subtraction with regrouping. Answer Keys Included. $ www.pinterest.com