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1.41.2×8.1+11×9.25+537×0.19

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1.41.2×8.1+11×9.25+537×0.19
2.55555×666667+44445×666666-155555
3.0.4×[11/52÷2又3/4×(4.3-1.8)]×26
4.(2×4×8×16×32)×(25×6.25×1.25×0.25)
5.85.42×7903.29-286.5×790.329+79032.9×4.323
6.1.135+2.246+3.346+4.475+5.557+6.768+7.768+8.979+9.979
7.1/18+1/54+1/108+1/270+1/378+1/504+1/648+1/810+1/990
8.(1+1)/2+(2-1)/2²+(3-1)/2³+…+(100-1)/2的一百次方
9.(1-1/2-1/3-…-1/1999)×(1/2+1/3+1/4+…+1/2000)-[(1-1/2-1/3-…-1/2000)(1/2+1/3+…+1/1999)]
10.20-{[(2²+1)/(2²-1)]+[(3²+1)/(3²-1)]+[(4²+1)/(4²-1)]+…+[(20²+1)/(20²-1)]}
1:原式=41.2*(10-1.9)+11*9.25+53.7*1.9=412+11*(10-0.75)+12.5*1.9=412+110-1.1*7.5+(20-7.5)*1.9=412+110+20*1.9-(1.1*7.5+1.9*7.5)=412+110+38-3*7.5=560-22.5=537.5
2:55555*666667+44445*666666-155555=
=55555*(666666+1)+44445*666666-155555
=55555*666666+55555+44445*666666-155555
=(55555+44445)*666666+55555-155555
=66666600000+55555-155555
=66666500000.
3:
4:2×4×8×16×32)×(25×6.25×1.25×0.25)=2*(4*25)*(8*1.25)*(16*6.25)*8*(4*0.25)=1600000
5:小知识:两数相乘,一个因数扩大若干倍,另一个因数缩小若干倍,积不变
85.42*7903.29-286.5*790.329+79032.9*4.323
=854.2*790.329-286.5*790.329+790.329*432.3
=790.329*(854.2-286.5+432.3)
=790.329*1000
=790329
6:1.135+3.346+5.557+7.768+9.979
1.135+3.346+5.557+(5.557+2.211)+(5.557+4.422)
//注:把7.768分成5.557+2.211,把9.979分成5.557+4.422
1.135+3.346+5.557+5.557+2.211+5.557+4.422
(1.135+4.422)+(3.346+2.211)+5.557+5.557+5.557
5.557+5.557+5.557+5.557+5.557
5.557×5=27.785
7:1/18+1/54+1/108+1/180+1/270+1/378+1/504+1/648+1/810+1/990
=1/9(1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90+1/110)
(1/2=1-1/2,1/6=1/2-1/3,1/12=1/3-1/4……)
=1/9(1-1/2+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+1/10-1/11)
=1/9(1-1/11)
=10/99
8:(3-5)²(1/2)²-(-0.125)100次方(-8)101次方
=(-2)^2(1/2)^2-(0.125)^100(-8)^100*(-8)
=(2*1/2)^2-(0.125*8)^100*(-8)
=1-1*(-8)
=1+8
=9
9:将 (1-1/2)+(1/2-1/3)+(1/3-1/4).+(1/1999-1/2000)分解(去括号)为1-2/1+2/1-3/1+3/1.+1/1999-1/2000.因为减1-2/1又加2/1,所以+2/1与-2/1互相抵消,-3/1+3/1也抵消.+1/19991与-/1999互相抵消..1没得抵消1/2000也没得抵消,只好照 算.所以:
(1-1/2)+(1/2-1/3)+(1/3-1/4).+(1/1999-1/2000)
=1-2/1+2/1-3/1+3/1.+1/1999-1/2000
=1-(2/1-2/1)-(3/1-3/1)-.(1/1999-1/1999)-1/2000
=1-1/2000
=1999/2000