Learning Advantage 4551 The Original Triangle Flash Cards, Addition and Subtraction, Grade: Kindergarten to 4, 6.5" Height, 1.25" Width, 6.25" Length Each card displays eight problems  four are addition and four are subtraction Relationship between addition and subtraction facts is emphasized Cards permit individualization of drill without changing cards. A harder fact is printed on one side of a card and an easier fact is printed on the other side Includes variations in activities For 2 or more players