Dưới đây là các bước tính cho các bài đã cho:

### Bài 2. Tính:

1)
\[
\frac{1}{2} - \frac{1}{3} - 5 = \frac{3}{6} - \frac{2}{6} - 5 = \frac{1}{6} - 5 = -\frac{29}{6}
\]

2)
\[
\frac{5}{4} + \frac{1}{2} - \frac{7}{8} = \frac{10}{8} + \frac{4}{8} - \frac{7}{8} = \frac{7}{8}
\]

3)
\[
\frac{1}{5} + \frac{1}{9} = \frac{9 + 5}{45} = \frac{14}{45}
\]

4)
\[
\frac{5}{4} - \frac{1}{7} = \frac{35 - 4}{28} = \frac{31}{28}
\]

5)
\[
-2 - \frac{7}{9} = -\frac{18}{9} - \frac{7}{9} = -\frac{25}{9}
\]

6)
\[
\frac{1}{2} - \frac{2}{5} = \frac{5 - 4}{10} = \frac{1}{10}
\]

7)
\[
\frac{5}{3} + \frac{7}{4} = \frac{20 + 21}{12} = \frac{41}{12}
\]

8)
\[
-1 - \frac{5}{3} = -\frac{3}{3} - \frac{5}{3} = -\frac{8}{3}
\]

9)
\[
\frac{1}{4} - \frac{7}{9} = \frac{9 - 28}{36} = -\frac{19}{36}
\]

10)
\[
-\frac{5}{4} - \frac{1}{7} = -\frac{35 + 4}{28} = -\frac{39}{28}
\]

11)
\[
\frac{1}{8} - \frac{1}{7} = \frac{7 - 8}{56} = -\frac{1}{56}
\]

12)
\[
-\frac{3}{10} - \frac{5}{6} = -\frac{18 + 25}{30} = -\frac{43}{30}
\]

### Bài 3. Tính nhanh:

1)
\[
-\frac{3}{5} + \frac{4}{8} = -\frac{3}{5} + \frac{1}{2} = -\frac{6}{10} + \frac{5}{10} = -\frac{1}{10}
\]

2)
\[
-\frac{5}{14} + \frac{1}{8} = -\frac{40}{112} + \frac{14}{112} = -\frac{26}{112} = -\frac{13}{56}
\]

3)
\[
-\frac{5}{22} - 1 + \frac{3}{22} = -1 - \frac{2}{22} = -1 - \frac{1}{11} = -\frac{12}{11}
\]

4)
\[
-\frac{1}{2} - \left( \frac{1}{4} + \frac{11}{77} \right) = -\frac{1}{2} - \frac{5+4}{20} = -\frac{15}{20} = -\frac{3}{4}
\]

5)
\[
\frac{2}{5} + \left( -\frac{2}{4} \times \frac{5}{4} \right) = \frac{2}{5} - \frac{10}{16} = \frac{2}{5} - \frac{5}{8}
\]

Chúc bạn học tốt!