Give your students engaging practice with 4-digit addition and subtraction with regrouping worksheets in the form of fun Math Mysteries! Perfect for 3rd grade math, 4th grade math, and 5th grade math, these printable activities combine problem solving, regrouping practice, and high-interest mystery stories. Students solve 16 regrouping problems to eliminate suspects and crack the case—just like an escape room or crack-the-code activity. These math mystery worksheets are designed for one cl