0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88
问题描述:
0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88
答
0.1+0.2+0.3+...+0.8+0.9+0.12+0.14+0.16+...+0.88
= ﹙ 0.1+0.9﹚*9/2+﹙0.12+0.88﹚*39/2
=4.5+19.5
=24