This download includes printable black and white addition and subtraction flash cards with facts 0+0/0-0 though 20+20/20-20 (plus and minus 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20). There are three different versions of the addition and subtraction flash cards. Choose the horizontal flash cards, vertical flash cards, or the flash cards with related facts all on one page! Print on cardstock or construction paper for extra durability. Answer keys are include