12．直接写出得数．
| 354-99= | 150×60= | 48+32-24= | 64÷8-8= |
| 24+16×6= | 100-5×4= | （57-27）÷3= | 80-80÷4= |
8．求未知数．
| x×14=490 | 180-x=24 | x+65=135 |
| 864÷x=32 | x÷14=770 | 0+x=2306 |
7．用简便方法计算下列各题．
0 153402 153410 153416 153420 153426 153428 153432 153438 153440 153446 153452 153456 153458 153462 153468 153470 153476 153480 153482 153486 153488 153492 153494 153496 153497 153498 153500 153501 153502 153504 153506 153510 153512 153516 153518 153522 153528 153530 153536 153540 153542 153546 153552 153558 153560 153566 153570 153572 153578 153582 153588 153596 199269
| 746+628+254+372 | 569-98-302 | 37×8×125 | 25×24 |
| 43×99 | 125×79+125 | 2870÷35 | （80+4）×25 |