3 1/8 + 2 1/12 - 1/3 = 3 3/24 + 2 2/24 - 8/24 =125/24-8/24 =117/24 = 4 21/24 = 4 7/8
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7,3 - 0.4 * 8,5 = 7,3 ( -0.4*8,5) = 7,3 - 3.4 = 3.9
4 7/8 : 3,9 =39/8 * 10/39 =10/8 = 5/4 = 1 1/4
12×0,8-1,8 -12
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2 1/12+2 1/15-1/4 2 1/12 + 1 49/60