【1.9+1.9*(4.8-3.81)】/(2.9-2.8)怎么简算?

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【1.9+1.9*(4.8-3.81)】/(2.9-2.8)怎么简算?

【1.9+1.9*(4.8-3.81)】/(2.9-2.8)怎么简算?
【1.9+1.9*(4.8-3.81)】/(2.9-2.8)怎么简算?

【1.9+1.9*(4.8-3.81)】/(2.9-2.8)怎么简算?

【1.9+1.9*(4.8-3.81)】/(2.9-2.8)
=[1.9*(1+4.8-3.81)]/0.1
=[1.9*1.99]*10
=19*2-19*0.01
=38-0.19
=37.81

【1.9+1.9×(4.8-3.81)】÷(2.9-2.8)
=(1.9+1.9×0.99)÷0.1
=【1.9×(1+0.99)】÷(1÷10)
=(1.9×1.99)÷1×10
=【(2-0.1)×(2-0.01)】×10
=【2×(2-0.01)-1×(2-0.01)】×10
=(4-0.02-2+0.01)×10
=4×10-0.02...

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【1.9+1.9×(4.8-3.81)】÷(2.9-2.8)
=(1.9+1.9×0.99)÷0.1
=【1.9×(1+0.99)】÷(1÷10)
=(1.9×1.99)÷1×10
=【(2-0.1)×(2-0.01)】×10
=【2×(2-0.01)-1×(2-0.01)】×10
=(4-0.02-2+0.01)×10
=4×10-0.02×10-2×10+0.01×10
=40-0.2-20+0.1
=40-20-0.2+0.1
=20-(0.2-0.1)
=20-0.1
=19.9
(有些麻烦,但是已是最简)

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