Content-rich math cards help teach students new skills in a fun way. This educational aid develops basic addition skills 13-18 and features the answer on the back of each card for self-checking. These cards are sturdy and come in a storage box. Students will find delight in mastering new skills. Details: Addition 13-18 design 6'' x 3'' x 0.5'' each card 99 cards No-see-through cards Quick-sorting, rounded corners Storage box For ages 6 and up