Eureka Teacher Cards, All-Purpose Notes, 36 Mailable Postcards (831830) Cards are an easy, inexpensive, and fun way for teachers to keep in touch with students Package of 36 identical cards Postcards are 4 x 6 inches and can be mailed with postcard postage Students enjoy the attention of a note from their teacher during summer or other breaks, or even during the school year Back of card looks like a standard postcard