-1-(-2)-(-3)-(-4)-.-(-19)-(-20)怎样解答

来源：学生作业学帮网编辑：学帮网时间：2024/05/30 01:01:24

(1+2+...+20)-2
=21*10-2
=208

1 2 3 4 1 2 3 4 1 2 3 4 1,2,3,4, 1 2 3 4 1 2 3 4 1,2,3,4, 1,2,3,4, 1,2,3,4, 1,2,3,4, 1 2 3 4 1,2,3,4, 1,2,3,4, 1,2,3,4, 1、2、3、4 1+2+3×4 1,2,3,4 1+2+3+4+.