Help your little one develop a knack for math with this add and subtract 4-digit and 3-digit numbers without regrouping worksheet. Subtraction is the inverse of addition and vice versa. Students apply this relationship to solve a set of problems in add and subtract 4-digit and 3-digit numbers without regrouping worksheet. This worksheet is about practicing the column method in which numbers are written one on top of another. In this method, students use their place value understanding to solve the problems.