(1+1·1)+(2+1·1x2)+(3+1·1x3)+…+(10+1·1x10)简算
问题描述:
(1+1·1)+(2+1·1x2)+(3+1·1x3)+…+(10+1·1x10)简算
答
1+2+3+4.+10+[1.1X(1+2+3+4.+10)]
=55+1.1X55
=55+60.5
=115.5