一道数学问题~要列式啊!!
简便算法<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5+1/6>-<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5>
参考答案:<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5+1/6>-<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5>
=<1/2+1/3+1/4+1/5>*(1/6)
=5/6*(1/6)+(9/20)*(1/6)
=77/360
简便算法<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5+1/6>-<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5>
参考答案:<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5+1/6>-<1/2+1/3+1/4+1/5>*<1/3+1/4+1/5>
=<1/2+1/3+1/4+1/5>*(1/6)
=5/6*(1/6)+(9/20)*(1/6)
=77/360