My teeth hurt when I watch students make their answers on the grids provided by test companies. I still play test Nazi even though I am retired and witness the same errors as students grid their answers. This practice has been created to develop the skill of griding answers only. The 3rd grade level works with 3-digit numbers, the 4th grade with 5-digit numbers, and the 5th grade with a decimal. Each grade level has two worksheets, one in addition and one in subtraction and they progressively become more difficult. Remember that the griding is the focus.