20-2/3-2/15-2/35-2/63-2/99=
问题描述:
20-2/3-2/15-2/35-2/63-2/99=
答
19.090909090909090909
上式=20-(1-1/3+1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11)
=20-(1-1/11)
=20-10/11
=210/11