1-1/2 1/2-1/3 1/3-1/4 用上面的规律计算1/2+1/6+1/12+1/2

问题描述:

1-1/2 1/2-1/3 1/3-1/4 用上面的规律计算1/2+1/6+1/12+1/2
1-1/2 1/2-1/3 1/3-1/4 用上面的规律计算1/2+1/6+1/12+1/20

1/2+1/6+1/12+1/20=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5=1-1/5=4/5