4 2/5 - 3 2/4 + 8 7/15 - 8 7/60 = ( 4 2/5 + 8 7/15) - ( 3 2/4 + 8 7/60) =
= ( 4 24/60 + 8 28/60) - ( 3 30/60 + 8 7/60) = 12 52/60 - 11 37/60 =
= 1 15/60 = 1 1/4
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2 3/4 - 4 1/4 = 2 3/4 - 3 5/4 = - 1 2/4 = - 1 1/2
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1 1/4 : ( - 1 1/2) = 5/4 : ( - 3/2) = ( - 5/6)
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Ответ ( - 5/6 )