สูตรคูณเเม่ 9
9 * 1 = 9
9 * 1 = 18
9 * 1 = 27
9 * 1 = 36
9 * 1 = 45
9 * 1 = 54
9 * 1 = 63
9 * 1 = 72
9 * 1 = 81
9 * 1 = 90
9 * 1 = 99
9 * 1 = 108