For example, since I want to make sure my students get accustomed to reviewing the various math concepts and standards we've learned all year, I have them practice regularly. I want them to get to a point where they are so familiar with grade level math content, that solving these types of problems becomes automatic.
There are other sources for worksheets also. You can find many public schools and private schools which will provide free worksheets for you if you buy textbooks from the school.
Solve vertical and horizontal computation problems
Worksheets also, when used properly, provide both the students and parent / tutor immediate feedback as to the child's progress. This means they can be used to point out areas where the student needs further reinforcement.
math worksheets grade 4
math worksheets for grade 2