Notched corners for quick organization. Large, easy to handle 6-1/4" x 3-1/4" cards. Bold, heavy type to use with large groups. Durable, thick card stock (14 pt.). Self-checking. Great for small groups, pairs, and whole class participation.  Set of 162 easy to read 6-1/4" x 3-1/4" (16cm x 8cm), double-sided flash cards, Cards feature practice for solving unknown quantities in one of three locations.