一、口算。
$18 + 72 =$
$70 ÷ 5 =$
$17 × 5 =$
$0 ÷ 86 =$
$25 × 5 =$
$83 × 6 =$
$130 - 50 =$
$80 × 50 =$
$182 ÷ 2 =$
$133 × 3 =$
$128 ÷ 4 =$
$15 × 60 =$
$297 ÷ 9 =$
$4 × 302 =$
$93 × 20 =$
$72 × 40 =$
$60 × 14 =$
$430 ÷ 2 =$
$\frac{7}{10} + \frac{1}{10} =$
$\frac{2}{6} + \frac{1}{6} =$
$\frac{5}{8} - \frac{3}{8} =$
$\frac{3}{8} + \frac{4}{8} =$
$\frac{9}{10} - \frac{3}{10} =$
$\frac{1}{9} + \frac{4}{9} =$

一、90 14 85
0 125 498
80 4000 91
399 32 900
33 1208 1860
2880 840 215

二、计算下面各题。
$13 × (31 + 3)$
$25 × (130 ÷ 2)$
$686 ÷ (49 - 42)$
$800 - 38 × 16$
$390 ÷ 5 × 30$
$(426 - 259) × 3$

二、442 1625 98
192 2340 501