1/2＋1/6＋1/12＋1/30＋1/42
网友回答
1/2＋1/6＋1/12＋1/20+1/30＋1/42
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1-1/7
=6/7======以下答案可供参考======
供参考答案1:
解 1/2＋1/6＋1/12＋1/30＋1/42
=1/2+1/2-1/3+1/3-1/4+1/5-1/6+1/6-1/7
=1-1/4+1/5-1/7
=3/4+2/35
=113/140
供参考答案2:
6/12+2/12+1/12+1/30+1/42
=9/12+1/30+1/42
=3/4+72/1260
=945/1260+72/1260
=1017/1260