数学问题很简单的
1/2-1/6-1/12-1/20-1/30-1/42
参考答案:1/2-1/6-1/12-1/20-1/30-1/42
=1/2-(1/2-1/3)-(1/3-1/4)-(1/4-1/5)-(1/5-1/6)-(1/6-1/7)
=1/7
1/2-1/6-1/12-1/20-1/30-1/42
参考答案:1/2-1/6-1/12-1/20-1/30-1/42
=1/2-(1/2-1/3)-(1/3-1/4)-(1/4-1/5)-(1/5-1/6)-(1/6-1/7)
=1/7