首页 > 留学知识库

问题: 1/42+1/56+1/72+1/90+1/110+1/132=? 求教六年级

解答:

1/42+1/56+1/72+1/90+1/110+1/132
=1/6*7+1/7*8+1/8*9+1/9*10+1/10*11+1/11*12
=1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10+1/10-1/11+1/11-1/12
=1/6-1/12
=1/12