a) = 35/40 - 32/40 + 2/40 = 5/40 = 1/8

б) = 22/36 - 15/36 - 4/36 = 3/36 = 1/12

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a) = 18/30 + 25/30 + 15/30 = 58/30 = 1 28/30 = 1 14/15

б) = 7/8 - 2/8 - 4/8 = 1/8