1 口算
建议用时4分钟 评价：☆☆☆
$\frac{5}{9} + \frac{2}{9} =$
$\frac{8}{21} - \frac{6}{21} =$
$0.875 + \frac{1}{8} =$
$\frac{5}{14} - \frac{2}{7} =$
$\frac{11}{14} + \frac{2}{7} =$
$\frac{1}{8} - \frac{1}{9} =$
$1 + \frac{3}{4} =$
$0.8 - \frac{3}{5} =$
$0.25 + \frac{5}{12} =$
$\frac{5}{6} - \frac{1}{3} =$
$2 - \frac{2}{9} =$
$\frac{3}{5} - \frac{1}{6} =$
$\frac{19}{5} - 3 =$
$\frac{1}{21} + \frac{2}{3} =$
$0.6 - \frac{1}{3} =$
$\frac{5}{18} + \frac{7}{27} =$
$\frac{1}{2} + \frac{1}{8} =$
$\frac{1}{6} + \frac{5}{12} =$
$\frac{9}{10} - \frac{1}{2} =$
$\frac{3}{7} + \frac{1}{2} =$

1. $\frac{7}{9}$
2. $\frac{2}{21}$
3. $1$
4. $\frac{1}{14}$
5. $\frac{15}{14}$
6. $\frac{1}{72}$
7. $\frac{7}{4}$
8. $0.2$
9. $\frac{2}{3}$
10. $\frac{1}{2}$
11. $\frac{16}{9}$
12. $\frac{13}{30}$
13. $\frac{4}{5}$
14. $\frac{5}{7}$
15. $\frac{4}{15}$
16. $\frac{29}{54}$
17. $\frac{5}{8}$
18. $\frac{7}{12}$
19. $\frac{2}{5}$
20. $\frac{13}{14}$

2 脱式计算（能简算的要简算）
建议用时6分钟 评价：☆☆☆
$13 - \frac{5}{13} - \frac{8}{13}$
$\frac{29}{24} - (\frac{5}{24} + \frac{4}{9})$
$\frac{13}{21} + \frac{9}{13} - \frac{8}{13} - \frac{13}{21}$
$0.75 - (\frac{7}{16} - \frac{1}{4})$
$\frac{3}{10} + \frac{5}{6} - \frac{8}{15}$
$\frac{11}{16} + \frac{3}{10} + \frac{5}{16} + \frac{1}{10}$
$1 - \frac{2}{5} + 0.75$
$\frac{5}{9} + (\frac{3}{4} - \frac{1}{3})$
$\frac{1}{4} + \frac{1}{3} + 0.75 + \frac{2}{3}$

1. $12$
2. $\frac{5}{9}$
3. $\frac{1}{13}$
4. $\frac{9}{16}$
5. $\frac{3}{5}$
6. $1\frac{2}{5}$
7. $1.35$
8. $\frac{35}{36}$
9. $2$