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1) 2 3/15 + 3 10/15 = 5 13/15 4 14/21 + 5 12/21 = 9 26/21 = 10 5/21 2) 6/3 - 1/3 = 5/3 3 54/63 - 2 56/63 = 2 117/63 - 2 56/63 = 61/63 3) 3 7/9 - 2/3 = 3 7/9 - 6/9 = 3 1/9 3 7/9 + 3 1/9 = 6 8/9