3．口算：
0 156594 156602 156608 156612 156618 156620 156624 156630 156632 156638 156644 156648 156650 156654 156660 156662 156668 156672 156674 156678 156680 156684 156686 156688 156689 156690 156692 156693 156694 156696 156698 156702 156704 156708 156710 156714 156720 156722 156728 156732 156734 156738 156744 156750 156752 156758 156762 156764 156770 156774 156780 156788 199269
| 300×50= | 320×20= | 42×20= | 20×50÷5= |
| 200÷5= | 200×5= | 51×2= | 15×4÷15×4= |
| 30×40= | 70+400= | 910÷70= | 30÷5+5= |
| 900×8= | 56÷2= | 6000÷30= | 351÷13×0= |
按要求填一填，画一画．