8 / 3 - (7 / 3 - 4 / 3) + 12 / 3 =9 / 2 + 13 / 2 - (4 / 2 + 1 / 2) =9 / 7 - 5 / 7 + (3 / 7 - 1 / 7 + 3 / 7 =14 / 11 - (3 / 11 + 1 / 11 + 2 / 11) + 8 / 11 =21 / 13 - (4 / 13 - 1 / 13) + 11 / 13 + 2 / 1?
8 / 3 - (7 / 3 - 4 / 3) + 12 / 3 = 9 / 2 + 13 / 2 - (4 / 2 + 1 / 2) = 9 / 7 - 5 / 7 + (3 / 7 - 1 / 7 + 3 / 7 = 14 / 11 - (3 / 11 + 1 / 11 + 2 / 11) + 8 / 11 = 21 / 13 - (4 / 13 - 1 / 13) + 11 / 13 + 2 / 13 =.