Subtract 1- or 2-digit number from a 2-digit number with/without renaming
Subtract 1-, 2-, or 3-digit numbers from 3- and 4-digit number with/without renaming
Or you can usually find textbooks and workbooks at the public library, where you can also copy any worksheets that you want to use.
For many middle-school children, math is a real challenge. It is at this age that the concepts begin to get more abstract, and work goes beyond "concrete" ideas like adding and subtracting. It's no surprise that at this age, math can become something the student avoids, or begins to dislike.