都简便计算

解：
（1）8+98+998+9998+99998
=10+100+1000+10000+100000-2*5
=111110-10
=11110

（2）999*222+333*334
=333*3*222+333*334
=333*666+333*334
=（666+334）*333
=1000*333
=333000
注意：分解转化

8+98+998+9998+99998

=8+90+8+900+90+8+9000+900+90+8+90000+9000+900+90+8
=90000+（9000+9000）+（900+900+900）+（90+90+90+90）+（8+8+8+8+8)
=90000+18000+2700+360+40
=108000+2700+360+40
=110700+360+40
=111060+40
=111100
125X56

=125X8X7
=1000X7
=7000
999X222+333X334
=333X(222X3+334)
=333X(666+334)
=333X1000
=333000

8+98+998+9998+99998
=10-2+100-2+1000-2+10000-2+100000-2
=111110-10=111100

999x222+333x334
=333x3x222+333x334
=333x（666+334）
=333x1000
=333000

8+98+998+9998+99998
=10+100+1000+10000+100000-2-2-2-2-2
=111110-10
=111100

999x222+333x334
=333x（3x222+334）
=333x1000
=333000本回答被提问者采纳