一、口算。
$35 - 19 =$
$68×0 =$
$25×4 =$
$58÷2 =$
$230÷2 =$
$21×60 =$
$400÷8 =$
$15×40 =$
$425÷5 =$
$6×800 =$
$490÷7 =$
$210×5 =$
$480÷8 =$
$430 + 80 =$
$282÷2 =$
$560 + 270 =$
$46×20 =$
$945÷9 =$
$\frac{8}{9} - \frac{6}{9} =$
$\frac{2}{4} - \frac{1}{4} =$
$\frac{5}{8} + \frac{2}{8} =$
$\frac{5}{10} + \frac{2}{10} =$
$\frac{5}{8} - \frac{1}{8} =$
$\frac{7}{10} + \frac{2}{10} =$

一、16 0 100
29 115 1260
50 600 85
4800 70 1050
60 510 141
830 920 105
$\frac{2}{9}$ $\frac{1}{4}$ $\frac{7}{8}$
$\frac{7}{10}$ $\frac{4}{8}$ $\frac{9}{10}$

二、用竖式计算，带 * 的要验算。
$74×33$
$60×25$
$*28×56$
$47×12$
$56×31$
$*73×59$

二、2442 1500 1568
564 1736 4307