(1) \( \frac{1}{80}-\frac{2}{5}= \) (1) \( \frac{7}{8}-\frac{3}{6}= \) (19) \( \frac{51}{15}-\frac{3}{5}= \) (14) \( \frac{15}{20}-\frac{1}{2}= \)

To solve the first equation, start by finding a common denominator for \( \frac{1}{80} \) and \( \frac{2}{5} \). The common denominator is 80, so \( \frac{2}{5} \) equals \( \frac{32}{80} \). Therefore, \[ \frac{1}{80}-\frac{32}{80}=\frac{1-32}{80}=\frac{-31}{80}. \] For the second equation, the two fractions are \( \frac{7}{8} \) and \( \frac{3}{6} \). Since \( \frac{3}{6} \) simplifies to \( \frac{1}{2} \) (with a common denominator of 8), you can rewrite it as \( \frac{7}{8} - \frac{4}{8} = \frac{3}{8} \). In the third equation, convert \( \frac{3}{5} \) to have a common denominator with \( \frac{51}{15} \). Rewrite \( \frac{3}{5} \) as \( \frac{9}{15} \). This gives us \[ \frac{51}{15} - \frac{9}{15} = \frac{42}{15}. \] For the last calculation, since \( \frac{1}{2} \) equals \( \frac{10}{20} \), you can see that \[ \frac{15}{20} - \frac{10}{20} = \frac{5}{20}. \] Finally, \( \frac{5}{20} \) simplifies to \( \frac{1}{4} \). So the final answers are: 1. \( \frac{1}{80}-\frac{2}{5} = \frac{-31}{80} \) 2. \( \frac{7}{8}-\frac{3}{6} = \frac{3}{8} \) 3. \( \frac{51}{15}-\frac{3}{5} = \frac{42}{15} \) 4. \( \frac{15}{20}-\frac{1}{2} = \frac{1}{4} \)