Whereís the answer sheet? Are the answers correct? Are the answers listed in a column that you have to match with the student worksheets or on a replica of the student page laced with answers? Last thing you need is to be in a hurry and red mark student worksheets...when their answers were correct all along.
Problems should use the Courier font. Why? Every Courier font character uses the same amount of space. A comma is the same width as the number 5. This means that all of the numbers line up perfectly for carrying during addition and bringing the zero down in division.