1/10+1/40+1/88+1/154+1/238+1/340=
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1/10+1/40+1/88+1/154+1/238+1/340=
1/10+1/40+1/88+1/154+1/238+1/340
=1/3×(3/10+3/40+3/88+3/154+3/238+3/340)
=1/3×(1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
=1/3×(1/2-1/20)
=1/3×9/20
=3/20
1/10+1/40+1/88+1/154+1/238+1/340
=1/3(1/2-1/5+1/5-1/8+...+1/17-1/20)
=1/3*9/20
=3/20
10=2×5
40=5×8
88=8×11
154=11×14
238=14×17
340=17×20
∴可得:
3/10=(1/2)-(1/5)
3/40=(1/5)-(1/8)
3/88=(1/8)-(1/11)
...
3/340=(1/17)-(1/20)
累加,可得:
3S=(1/2)-(1/20)=9/20
S=3/20
1/10+1/40+1/88+1/154+1/238+1/340
=1/(2×5)+1/(5×8)+1/(8×11)+1/(11×14)+1/(14×17)+1/(17×20)
=1/3×(1/2-1/5)+1/3(1/5-1/8)+1/3(1/8-1/11)+1/3(1/11-1/14)+1/3(1/14-1/17)+1/3(1/17-1/20)
=1/3(1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
=1/3×(1/2-1/20)
=3/20
1/10+1/40+1/88+1/154简算
1/10+1/40+1/88+1/154+1/238+1/340=
1-1/10+3-1/40+5-1/88+7-1/154+9-1/238+11-1/340
1又1/10+4又1/40+7又1/88+10又1/154+.+28又1、928=?
1又10分之1+3又40分之1+5又88分之1+7又154分之1+11又340分之1,简便计算
1/1/10+3/1/40+5/1/88+9/1/154简算原题。1/1/2x5+3/1/5x8+5/1/8x11+9/1/11x14简算
1/10+1/40+1/88+`````+1/460
10/1+40/1+88/1+.+928/1
1/10+1/40+1/88+...+1/928 速算
145*154/D2:1
请各位教教我怎么巧算下列各题!谢了!烦请各位高手教老弟一下!1/5×7+(1+1/5)×3 1/10+1/40+1/88+1/154+1/238+1/340 93又1/11÷16100²+98²+96²+94²+92²-(99²+97²+95²+93²+91²
1/10+1/40+1/88+...+1/460要怎样简算
简便运算:第一题,13又1/6+15又1/12+17又1/20+19又1/30第二题,1/1x4+1/4x7+1/7x10+...+1/97x100第三题,2/3+2/15+2/35+2/63+2/99+2/143第四题,1又1/10+3又1/40+5又1/88+7又1/154+9又1/238+11又1/340
1又3/10+3又3/40+5又3/88+7又3/154+9又3/238+11又3/340 拆分求值,麻烦说的详细点.
1+1=?10+88=?()
3/88+3/154+3/238+3/340+1/20=?
40÷(1-1/10)
简便计算:3/10+3/40+3/88+3/154