计算下面数字方阵中所有自然数和.1,2,3,.,38,39,40 2,3,4,.39,40,41 3,4,5,.,40,41,4

问题描述:

计算下面数字方阵中所有自然数和.1,2,3,.,38,39,40 2,3,4,.39,40,41 3,4,5,.,40,41,4

(1+40)*40/2=820
(2+41)*40/2=860
(3+42)*40/2=900
820+860+900=2580