作业帮计算1／5×8+1／8×11+1／11×14+1／14×17+1／17×20,它的结果是多少,
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计算1／5×8+1／8×11+1／11×14+1／14×17+1／17×20,它的结果是多少,
计算1／5×8+1／8×11+1／11×14+1／14×17+1／17×20,它的结果是多少,
计算1／5×8+1／8×11+1／11×14+1／14×17+1／17×20,它的结果是多少,
1／5×8+1／8×11+1／11×14+1／14×17+1／17×20
=1/3(1/5-1/8+1/8-1/11+...+1/17-1/20)
=1/3(1/5-1/20)
=1/3*3/20
=1/20
1/3是（8-5）,（11-8）,等的倒数.1/3×（1/5-1/8)=1／5×8
1/3(1/5-1/8+1/8-1/11~~~-1/20)
=1/20
1／5×8+1／8×11+1／11×14+1／14×17+1／17×20
=1/3(1/5-1/8+1/8-1/11+...+1/17-1/20)
=1/3(1/5-1/20)
=1/3*3/20
=1/20哪来的1/3，请用文字叙述！要详细8与5的差是1/3, 11与8的差是1/3 1/5-1/8=1/3(1/5-1/8) 其他也是这样8与5的差是3, ...
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1／5×8+1／8×11+1／11×14+1／14×17+1／17×20
=1/3(1/5-1/8+1/8-1/11+...+1/17-1/20)
=1/3(1/5-1/20)
=1/3*3/20
=1/20
收起
1／5×8+1／8×11+1／11×14+1／14×17+1／17×20，
=（1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20）/3
=（1/5-1/20）/3
=1/20
1/5*8+1/8*11+1/11*14+1/14*17+1/17*20 = 6.6384835752483
=(1/5-1/8)÷3+（1/8-1/11)÷3+(1/11-1/14)÷3+(1/14-1/17)÷3+(1/17-1/20)÷3
=(1/5-1/20)÷3
=1/20