1. 直接写出得数。
$\frac{1}{12}+\frac{2}{5}=$
$\frac{2}{3}+\frac{1}{4}=$
$3+\frac{1}{7}=$
$\frac{4}{9}+\frac{3}{4}=$
$\frac{4}{5}-\frac{1}{10}=$
$\frac{3}{5}-\frac{1}{2}=$
$\frac{11}{12}-\frac{3}{7}=$
$\frac{4}{9}-\frac{1}{3}=$
$\frac{3}{10}+\frac{3}{20}=$
$\frac{9}{4}+\frac{3}{4}=$
$\frac{4}{13}+\frac{1}{26}=$
$\frac{5}{8}-\frac{1}{11}=$

$\frac{1}{12}+\frac{2}{5}=\frac{5}{60}+\frac{24}{60}=\frac{29}{60}$
$\frac{2}{3}+\frac{1}{4}=\frac{8}{12}+\frac{3}{12}=\frac{11}{12}$
$3+\frac{1}{7}=\frac{21}{7}+\frac{1}{7}=\frac{22}{7}$
$\frac{4}{9}+\frac{3}{4}=\frac{16}{36}+\frac{27}{36}=\frac{43}{36}$
$\frac{4}{5}-\frac{1}{10}=\frac{8}{10}-\frac{1}{10}=\frac{7}{10}$
$\frac{3}{5}-\frac{1}{2}=\frac{6}{10}-\frac{5}{10}=\frac{1}{10}$
$\frac{11}{12}-\frac{3}{7}=\frac{77}{84}-\frac{36}{84}=\frac{41}{84}$
$\frac{4}{9}-\frac{1}{3}=\frac{4}{9}-\frac{3}{9}=\frac{1}{9}$
$\frac{3}{10}+\frac{3}{20}=\frac{6}{20}+\frac{3}{20}=\frac{9}{20}$
$\frac{9}{4}+\frac{3}{4}=\frac{12}{4}=3$
$\frac{4}{13}+\frac{1}{26}=\frac{8}{26}+\frac{1}{26}=\frac{9}{26}$
$\frac{5}{8}-\frac{1}{11}=\frac{55}{88}-\frac{8}{88}=\frac{47}{88}$

2. 分数、小数互化。
$0.04=$
$2.5=$
$0.125=$
$\frac{12}{25}=$
$\frac{3}{2}=$
$\frac{7}{1000}=$

$0.04=\frac{4}{100}=\frac{1}{25}$
$2.5=\frac{25}{10}=\frac{5}{2}$
$0.125=\frac{125}{1000}=\frac{1}{8}$
$\frac{12}{25}=12÷25=0.48$
$\frac{3}{2}=3÷2=1.5$
$\frac{7}{1000}=7÷1000=0.007$

3. 填空。

$\frac{1}{3} + \frac{1}{4} = \frac{4}{12} + \frac{3}{12} = \frac{7}{12}$
$\frac{7}{12} - \frac{1}{6} = \frac{7}{12} - \frac{2}{12} = \frac{5}{12}$
$\frac{5}{12} + \frac{1}{2} = \frac{5}{12} + \frac{6}{12} = \frac{11}{12}$
最终填空依次为：$\frac{7}{12}$，$\frac{5}{12}$，$\frac{11}{12}$

4. 脱式计算。
$\frac{7}{10}-\frac{1}{2}+\frac{3}{10}$
$\frac{5}{9}-(\frac{1}{3}-\frac{4}{9})$
$\frac{1}{2}-\frac{3}{8}-\frac{1}{8}$
$\frac{2}{3}+\frac{3}{5}-\frac{7}{9}$
$\frac{7}{2}+\frac{3}{8}-\frac{3}{4}$
$\frac{7}{5}+\frac{1}{4}-\frac{1}{9}$

$\frac{7}{10}-\frac{1}{2}+\frac{3}{10}$
$=\frac{7}{10}+\frac{3}{10}-\frac{1}{2}$
$=1-\frac{1}{2}$
$=\frac{1}{2}$
$\frac{5}{9}-(\frac{1}{3}-\frac{4}{9})$
$=\frac{5}{9}-\frac{1}{3}+\frac{4}{9}$
$=\frac{5}{9}+\frac{4}{9}-\frac{1}{3}$
$=1-\frac{1}{3}$
$=\frac{2}{3}$
$\frac{1}{2}-\frac{3}{8}-\frac{1}{8}$
$=\frac{1}{2}-(\frac{3}{8}+\frac{1}{8})$
$=\frac{1}{2}-\frac{4}{8}$
$=\frac{1}{2}-\frac{1}{2}$
$=0$
$\frac{2}{3}+\frac{3}{5}-\frac{7}{9}$
$=\frac{30}{45}+\frac{27}{45}-\frac{35}{45}$
$=\frac{57}{45}-\frac{35}{45}$
$=\frac{22}{45}$
$\frac{7}{2}+\frac{3}{8}-\frac{3}{4}$
$=\frac{28}{8}+\frac{3}{8}-\frac{6}{8}$
$=\frac{31}{8}-\frac{6}{8}$
$=\frac{25}{8}$
$\frac{7}{5}+\frac{1}{4}-\frac{1}{9}$
$=\frac{252}{180}+\frac{45}{180}-\frac{20}{180}$
$=\frac{297}{180}-\frac{20}{180}$
$=\frac{277}{180}$

5. 在〇里填上“＞”“＜”或“=”。
$0.375 ◯ \frac{3}{8}$
$0.2 ◯ \frac{1}{5}$
$0.09 ◯ \frac{1}{10}$
$\frac{7}{20} ◯ 0.035$
$\frac{7}{4} ◯ 1.2$
$3.35 ◯ \frac{9}{10}$

$0.375 = \frac{3}{8}$，$0.375 = \frac{3}{8}$
$0.2 = \frac{1}{5}$，$0.2 = \frac{1}{5}$
$\frac{1}{10}=0.1$，$0.09＜0.1$，$0.09＜\frac{1}{10}$
$\frac{7}{20}=0.35$，$0.35＞0.035$，$\frac{7}{20}＞0.035$
$\frac{7}{4}=1.75$，$1.75＞1.2$，$\frac{7}{4}＞1.2$
$\frac{9}{10}=0.9$，$3.35＞0.9$，$3.35＞\frac{9}{10}$