简算:1/15+1/35+1/63+1/99
问题描述:
简算:1/15+1/35+1/63+1/99
答
1/15+1/35+1/63+1/99
=(1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)÷2
=(1/3-1/11)÷2
=4/33