5.30×20的末尾有( )个 0.
A. | 1 | B. | 2 | C. | 3 |
19.口算.
0 158480 158488 158494 158498 158504 158506 158510 158516 158518 158524 158530 158534 158536 158540 158546 158548 158554 158558 158560 158564 158566 158570 158572 158574 158575 158576 158578 158579 158580 158582 158584 158588 158590 158594 158596 158600 158606 158608 158614 158618 158620 158624 158630 158636 158638 158644 158648 158650 158656 158660 158666 158674 199269
40×20 | 81÷9 | 30×40 | 24×10 |
640÷8 | 40×7 | 770÷7 | 360÷6 |
50×30 | 100×5 | 60×3 | 450÷9 |
6.4+2.2 | 3.5-2.1 | 4.2+1.4 | 8.6-5.1 |