9 11/12 - 3 10/12 = 6 1/10
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9 11/15 - 4 = 5 11/15
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11 - 5/8 = 10 8/8 - 5/8 = 10 3/8
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8 3/17 -4 11/17 = 7 20/17 - 4 11/17 = 3 9/17
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21 - 8 7/15 = 20 15/15 - 8 7/15 = 12 8/15
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10 15/16 - 3 15/16 = 7
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