There are 100 flash cards that are arranged 4 to a page. There are problems with missing sums and problems with missing addends. The answers can be printed on the back to make these self checking flashcards. On the back, the original problem is in gray while the answer is in black. This helps to reinforce the visual learning. There is an answer sheet that can be used for students to record answers. There is also an answer key for easy grading/checking. All flashcards are numbered to help keep things organized.