1/2+1/6+1/12+1/20+1/30等于多少,不能用通分

1/2+1/6+1/12+1/20+1/30等于多少,不能用通分
1/2+1/6+1/12+1/20+1/30等于多少,不能用通分

1/2+1/6+1/12+1/20+1/30等于多少,不能用通分
1/2=1-1/2
1/6=1/2-1/3
1/12=1/3-1/4
1/20=1/4-1/5
1/30=1/5-1/6
把所有等式相加即得1/2+1/6+1/12+1/20+1/30=1-1/6=5/6

1/2+1/6+1/12+1/20+1/30
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1-1/6
=5/6