The objective for knowledge in subtracting 3 to 4 digit numbers from 3 to 4 digit numbers with regrouping is to be able to accurately and efficiently perform subtraction calculations involving numbers within this range. This includes understanding the concept of regrouping or borrowing when necessary, and being able to apply the appropriate steps and strategies to solve subtraction problems with regrouping. The objective also includes developing fluency in subtracting larger numbers and being able to solve real-world problems that require subtracting 3 to 4 digit numbers with regrouping.