网友们,请帮我回答以下数学问题!简算以下算式8.1/0.45=（0.65*57.4+0.574*35-57.4）/3=0.666*0.7+0.222*0.9=2150*3.8+215*51+2.15*1400+850*9.6+0.85*700=11.8*43-860*0.09=11/2+21/6+31/12+41/20+51/30+61/42=注：11/2为一又二分

Question

网友们,请帮我回答以下数学问题!
简算以下算式
8.1/0.45=
（0.65*57.4+0.574*35-57.4）/3=
0.666*0.7+0.222*0.9=
2150*3.8+215*51+2.15*1400+850*9.6+0.85*700=11.8*43-860*0.09=
1 1/2+2 1/6+3 1/12+4 1/20+5 1/30+6 1/42=
注：1 1/2为一又二分之一,以此类推,全要过程!

Answer 1

8.1/0.45
=8.1÷(0.9×0.5)
=8.1÷0.9÷0.5
=9÷0.5
=18





（0.65*57.4+0.574*35-57.4）/3
=（0.65*57.4+57.4*0.35-57.4*1）/3
=57.4*（0.65+0.35-1）/3
=57.4*0/3
=0

0.666*0.7+0.222*0.9
=0.222*3*0.7+0.222*0.9
=0.222*(2.1+0.9)
=0.222*3
=0.666





2150*3.8+215*51+2.15*1400+850*9.6+0.85*700
=215*38+215*51+215*14+85*96+85*7
=215x(38+51+14)+85x(96+7)
=215x103+85x103
=(215+85)x103
=200x103
=20600


11.8*43-860*0.09
=11.8x43-43x20x0.09
=43x(11.8-1.8)
=43x10
=430


1 1/2+2 1/6+3 1/12+4 1/20+5 1/30+6 1/42
=(1+2+3+4+5+6)+(1/2+1/2x3+1/3x4+……+1/6x7）
=21+(1/2+1/2-1/3+1/3-1/4+……+1/6-1/7)
=21+(1/2+1/2-1/7)
=21+6/7
=21又7分之6