口算460+30= 380+400= 670﹣50= 72÷9=6+9×4= 40+3×6= 8+48÷6= 7000﹣5000=
(7.5+7.5+7.5+7.5)×125×4.
1999+999×999.
8888008×125.
3.75×4.23×36﹣125×0.423×2.8.
25×2.64+12.5×0.726+0.125.