一、口算。
$60.8 - 40.9 =$
$1480 ÷ 4 =$
$1.1 × 0.09 =$
$2.3 × 0.7 =$
$24 ÷ 0.12 =$
$8.19 ÷ 0.3 =$
$7.12 + 1.8 =$
$0.88 ÷ 4.4 =$
$2.4 × 5 =$
$272 + 172 =$
$0.26 + 0.78 =$
$12.19 - 2.91 =$
$\frac{9}{25} ÷ 12 =$
$30 × \frac{7}{60} =$
$\frac{11}{25} × \frac{10}{33} =$
$\frac{4}{5} - 0.75 =$
$\frac{1}{3} × 7.5 =$
$\frac{6}{7} + \frac{5}{21} =$
$\frac{1}{6} ÷ \frac{1}{30} =$
$\frac{7}{10} × \frac{5}{14} =$
$\frac{10}{7} ÷ \frac{5}{7} =$
$\frac{3}{5} × \frac{5}{6} =$
$\frac{7}{12} ÷ \frac{7}{8} =$
$\frac{2}{3} × 9 =$

1. $60.8 - 40.9 = 19.9$
2. $1480 ÷ 4 = 370$
3. $1.1 × 0.09 = 0.099$
4. $2.3 × 0.7 = 1.61$
5. $24 ÷ 0.12 = 200$
6. $8.19 ÷ 0.3 = 27.3$
7. $7.12 + 1.8 = 8.92$
8. $0.88 ÷ 4.4 = 0.2$
9. $2.4 × 5 = 12$
10. $272 + 172 = 444$
11. $0.26 + 0.78 = 1.04$
12. $12.19 - 2.91 = 9.28$
13. $\frac{9}{25} ÷ 12 = \frac{3}{100}$
14. $30 × \frac{7}{60} = \frac{7}{2}$
15. $\frac{11}{25} × \frac{10}{33} = \frac{2}{15}$
16. $\frac{4}{5} - 0.75 = \frac{1}{20}$
17. $\frac{1}{3} × 7.5 = \frac{5}{2}$
18. $\frac{6}{7} + \frac{5}{21} = \frac{23}{21}$
19. $\frac{1}{6} ÷ \frac{1}{30} = 5$
20. $\frac{7}{10} × \frac{5}{14} = \frac{1}{4}$
21. $\frac{10}{7} ÷ \frac{5}{7} = 2$
22. $\frac{3}{5} × \frac{5}{6} = \frac{1}{2}$
23. $\frac{7}{12} ÷ \frac{7}{8} = \frac{2}{3}$
24. $\frac{2}{3} × 9 = 6$

二、计算下面各题，能简算的要简算。
$7÷\frac{7}{6} - \frac{7}{6}÷7$
$0.4×\frac{7}{9} + \frac{2}{9}×\frac{2}{5}$
$\frac{2}{7} + \frac{3}{8}×\frac{4}{9} + \frac{1}{2}$
$(3.8 - 7.7÷2.5)×2$
$30.6 + 9.6÷3.2 - 14.82$
$3.5×11 + 8×3.5 + 3.5$

1. $7÷\frac{7}{6} - \frac{7}{6}÷7 = 5\frac{5}{6}$
2. $0.4×\frac{7}{9} + \frac{2}{9}×\frac{2}{5} = \frac{2}{5}$
3. $\frac{2}{7} + \frac{3}{8}×\frac{4}{9} + \frac{1}{2} = \frac{20}{21}$
4. $(3.8 - 7.7÷2.5)×2 = 1.44$
5. $30.6 + 9.6÷3.2 - 14.82 = 18.78$
6. $3.5×11 + 8×3.5 + 3.5 = 70$