小学数学1/5*8+1/8*11+1/14*17+1/17*20怎么解

Question

如题所述

Answer 1

（1）1/5*8+1/8*11+1/14*17+1/17*20
=8/5+11/8+17/14+20/17
=64/40+55/40+17/14+20/17
=119/40+17/14+20/17
=833/280+340/280+20/17
=1173/280+20/17
=19941/4760+5600/4760
=25541/4760
估计你可能是忘记加括号吧？
（2）1/(5*8)+1/(8*11)+1/(14*17)+1/(17*20)
=[3/(5*8)+3/(8*11)+3/(14*17)+3/(17*20)]/3
=[(1/5-1/8)+(1/8-1/11)+(1/14-1/17)+(1/17+1/20)]/3
=[1/5-1/8+1/8-1/11+1/14-1/17+1/17+1/20]/3
=[1/5-1/11+1/14+1/20]/3
=[1/5+1/20-1/11+1/14]/3
=[4/20+1/20-1/11+1/14]/3
=[5/20-1/11+1/14]/3
=[1/4-1/11+1/14]/3
=[1/4+1/14-1/11]/3
=[7/28+2/28-1/11]/3
=[9/28-1/11]/3
=[99/308-28/308]/3
=[71/308]/3
=71/924

Answer 2

1/5×1/8=1/3×（1/5-1/8）
1/8*11=1/3×（1/8-1/11）
1/11*14=1/3×（1/11-1/14）
1/14*17=1/3×（1/14-1/17）
1/17*20=1/3×（1/17-1/20）
你给的题目是不是漏了1/11*14
原式=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×【（1/5-1/8）+（1/8-1/11）+（1/11-1/14）+（1/14-1/17）+（1/17-1/20）】
=1/3×（1/5-1/20）
=1/3×3/20
=1/20

Answer 3

1/5*8+1/8*11+1/11*14+1/14*17+1/17*20
=1/3x(1/5-1/8)+1/3x(1/8-1/11)++1/3x(1/11-1/14)+1/3x(1/14-1/17)+1/3x(1/17-1/20)
=1/3x(1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
=1/3x(1/5-1/20)
=1/3x3/20
=1/20

Answer 4

1/5*8+1/8*11+1/11*14+1/14*17+1/17*20
=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*(1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
=1/3*(1/5-1/20)
=1/3*3/20
=1/20

Answer 5

图

追答

漏了1/(11×14)

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