Вопрос:

6. Вычислить: a) \(\frac{11}{4} - \frac{2}{5}\) б) \(\frac{1}{5} - \frac{3}{4}\) в) \(\frac{1}{4} - \frac{3}{25}\) г) \(\frac{9}{4} + \frac{8}{5}\)

Ответ:

Решение:

  1. а) \(\frac{11}{4} - \frac{2}{5} = \frac{11 × 5}{4 × 5} - \frac{2 × 4}{5 × 4} = \frac{55}{20} - \frac{8}{20} = \frac{55-8}{20} = \frac{47}{20}\)
  2. б) \(\frac{1}{5} - \frac{3}{4} = \frac{1 × 4}{5 × 4} - \frac{3 × 5}{4 × 5} = \frac{4}{20} - \frac{15}{20} = \frac{4-15}{20} = -\frac{11}{20}\)
  3. в) \(\frac{1}{4} - \frac{3}{25} = \frac{1 × 25}{4 × 25} - \frac{3 × 4}{25 × 4} = \frac{25}{100} - \frac{12}{100} = \frac{25-12}{100} = \frac{13}{100}\)
  4. г) \(\frac{9}{4} + \frac{8}{5} = \frac{9 × 5}{4 × 5} + \frac{8 × 4}{5 × 4} = \frac{45}{20} + \frac{32}{20} = \frac{45+32}{20} = \frac{77}{20}\)

Ответ: а) \(\frac{47}{20}\), б) -\(\frac{11}{20}\), в) \(\frac{13}{100}\), г) \(\frac{77}{20}\).