Контрольные задания
Вопрос:Фото задания: 4. Вычислите: а) 1/2 + 1/3 + 1/5; б) 1/3 + 3/4 + 5/12; в) 3/5 + 5/6 + 1/2; а) 1/3 − 1/5 − 1/15; б) 1/2 − 2/5 − 1/10; в) 7/8 −…Фото задания

Ответ:

  1. а) \(\frac{1}{2}+\frac{1}{3}+\frac{1}{5}=\frac{15}{30}+\frac{10}{30}+\frac{6}{30}=\frac{31}{30}=1\frac{1}{30}\).
  2. б) \(\frac{1}{3}+\frac{3}{4}+\frac{5}{12}=\frac{4}{12}+\frac{9}{12}+\frac{5}{12}=\frac{18}{12}=1\frac{1}{2}\).
  3. в) \(\frac{3}{5}+\frac{5}{6}+\frac{1}{2}=\frac{18}{30}+\frac{25}{30}+\frac{15}{30}=\frac{58}{30}=1\frac{14}{15}\).
  4. а) \(\frac{1}{3}-\frac{1}{5}-\frac{1}{15}=\frac{5}{15}-\frac{3}{15}-\frac{1}{15}=\frac{1}{15}\).
  5. б) \(\frac{1}{2}-\frac{2}{5}-\frac{1}{10}=\frac{5}{10}-\frac{4}{10}-\frac{1}{10}=0\).
  6. в) \(\frac{7}{8}-\frac{1}{4}-\frac{1}{2}=\frac{7}{8}-\frac{2}{8}-\frac{4}{8}=\frac{1}{8}\).
  7. а) \(3\frac{1}{3}+2\frac{1}{6}=5+\frac{2}{6}+\frac{1}{6}=5\frac{1}{2}\).
  8. б) \(\frac{3}{5}+4\frac{1}{2}=4+\frac{6}{10}+\frac{5}{10}=5\frac{1}{10}\).
  9. в) \(1\frac{3}{7}+2\frac{1}{2}=3+\frac{6}{14}+\frac{7}{14}=3\frac{13}{14}\).
  10. а) \(1\frac{1}{8}-\frac{3}{4}=1\frac{1}{8}-\frac{6}{8}=\frac{3}{8}\).
  11. б) \(1\frac{3}{5}-\frac{2}{3}=\frac{24}{15}-\frac{10}{15}=\frac{14}{15}\).
  12. в) \(2\frac{1}{6}-1\frac{3}{4}=\frac{13}{6}-\frac{7}{4}=\frac{26}{12}-\frac{21}{12}=\frac{5}{12}\).