84又18/19乘以10.375+105又1/19乘以3/8;1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17全部都要简便计算
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84又18/19乘以10.375+105又1/19乘以3/8;1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17全部都要简便计算
84又18/19乘以10.375+105又1/19乘以3/8;1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17
全部都要简便计算
84又18/19乘以10.375+105又1/19乘以3/8;1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17全部都要简便计算
84又18/19乘以10.375+105又1/19乘以3/8;
=84又18/19×10+84又18/19×3/8+105又1/19×3/8
=(85-1/19)×10+(84又18/19+105又1/19)×3/8
=850-10/19+190×3/8
=850+71又1/4-10/19
=920又55/76
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
=(1+3+5+7+9+11+13+15+17)+(1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90)
=9×9+(1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10)
=81+(1/2-1/10)
=81+0.4
=81.4