计算：;f'L)h'S'f7p+B0G'}9D8e7V3u+f
1991+8119+8009+1881;f'L)h'S'f7p+B0G'}9D8e7V3u+f
算式：提示-V'j-R5s(N(s;f'L)h'S'f7p+B0G'}9D8e7V3u+f
=6b4U(A/I;f'L)h'S'f7p+B0G'}9D8e7V3u+f