一、口算。
$75 + 22 =$
$84 ÷ 4 =$
$60 - 17 =$
$9 × 32 =$
$75 × 5 =$
$90 ÷ 5 =$
$90 × 10 =$
$350 ÷ 7 =$
$360 + 70 =$
$550 ÷ 5 =$
$23 × 20 =$
$203 × 4 =$
$460 ÷ 2 =$
$360 × 3 =$
$608 ÷ 2 =$
$20 × 52 =$
$180 ÷ 4 =$
$85 × 20 =$
$\frac{8}{9} - \frac{6}{9} =$
$\frac{5}{7} + \frac{1}{7} =$
$\frac{1}{4} + \frac{2}{4} =$
$\frac{8}{10} - \frac{5}{10} =$
$\frac{7}{8} - \frac{4}{8} =$
$\frac{4}{10} + \frac{3}{10} =$

一、97 21 43
288 375 18
900 50 430
110 460 812
230 1080 304
1040 45 1700
$\frac{2}{9}$ $\frac{6}{7}$ $\frac{3}{4}$
$\frac{3}{10}$ $\frac{3}{8}$ $\frac{7}{10}$

二、用竖式计算，带 * 的要验算。
$50 × 65$
$43 × 12$
*$36 × 59$
$75 × 21$
$53 × 42$
*$27 × 35$

二、3250 516 2124
1575 2226 945