98+998+9998+99998
=(100-2)+(1000-2)+(10000-2)+(100000-2)
=100-2+1000-2+10000-2+100000-2
=(100+1000+10000+100000)-(2+2+2+2+)
=111100-8
=111092
这是几年级滴题目啊?