Ответ:

Пошаговое объяснение:

7/9 + 5/12 = 28/36 + 15/36 = 43/36 = 1 7/36

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11/12 - 5/18 = 33/36 - 10/36 = 23/36

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3/8 + 19/20 = 15/40 + 38/40 = 53/40 = 1 13/40

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5/6 - 8/15 = 25/30 - 16/30 = 9/30 = 3/10