一、口算。
$92 - 73 =$
$86×2 =$
$10×80 =$
$37×2 =$
$56÷2 =$
$36 + 26 =$
$85÷5 =$
$23×8 =$
$15×8 =$
$440 - 360 =$
$420÷6 =$
$140×7 =$
$31×50 =$
$17×40 =$
$848÷4 =$
$404×0 =$
$122 + 365 =$
$630÷6 =$
$\frac{1}{3} + \frac{1}{3} =$
$\frac{1}{2} - \frac{1}{2} =$
$\frac{6}{7} - \frac{3}{7} =$
$\frac{2}{10} + \frac{5}{10} =$
$\frac{1}{7} + \frac{1}{7} =$
$\frac{2}{6} - \frac{2}{6} =$

一、19 172 800
74 28 62
17 184 120
80 70 980
1550 680 212
0 487 105
$\frac{2}{3} 0 \frac{3}{7}$
$\frac{7}{10} \frac{2}{7} 0$

二、计算下面各题。
$780÷3 - 194$
$438 - (15 + 176)$
$38×(233 - 198)$
$174÷(2×3)$
$735÷7 + 255$
$1000 - 28×24$

二、66 247 1330
29 360 328