Ответ:

  1. \(\frac{21}{27}-\frac{2}{3}=\frac{7}{9}-\frac{6}{9}=\frac{1}{9}\).
  2. \(\frac{63}{81}-\frac{6}{9}=\frac{7}{9}-\frac{6}{9}=\frac{1}{9}\).
  3. \(\frac{48}{49}-\frac{4}{7}=\frac{48}{49}-\frac{28}{49}=\frac{20}{49}\).
  4. \(\frac{10}{64}-\frac{1}{8}=\frac{5}{32}-\frac{4}{32}=\frac{1}{32}\).
  5. \(\frac{7}{3}-\frac{14}{27}=\frac{63}{27}-\frac{14}{27}=\frac{49}{27}=1\frac{22}{27}\).
  6. \(\frac{8}{10}-\frac{1}{100}=\frac{80}{100}-\frac{1}{100}=\frac{79}{100}\).
  7. \(\frac{40}{100}-\frac{1}{5}=\frac{2}{5}-\frac{1}{5}=\frac{1}{5}\).