3.48 Подставьте вместо знака вопроса знак действия так, чтобы получилось верное равенство: a) 1\(\frac{5}{6}\) ? \(\frac{6}{11}\) = 1; б) 3 ? 2\(\frac{1}{4}\) = \(\frac{3}{4}\); в) \(\frac{5}{9}\) ? \(\frac{7}{9}\) = \(\frac{5}{7}\); г) \(\frac{5}{14}\) ? 0,7 = \(\frac{1}{4}\).

а) \(1\frac{5}{6} - \frac{6}{11} = 1\)

\(\frac{11}{6} - \frac{6}{11} = \frac{11\cdot11 - 6\cdot6}{66} = \frac{121 - 36}{66} = \frac{85}{66}
e 1\)

\(1\frac{5}{6} + \frac{6}{11} = 1\)

\(\frac{11}{6} + \frac{6}{11} = \frac{11\cdot11 + 6\cdot6}{66} = \frac{121 + 36}{66} = \frac{157}{66}
e 1\)

\(1\frac{5}{6} : \frac{6}{11} = 1\)

\(\frac{11}{6} : \frac{6}{11} = \frac{11}{6} \cdot \frac{11}{6} = \frac{121}{36}
e 1\)

\(1\frac{5}{6} \cdot \frac{6}{11} = 1\)

\(\frac{11}{6} \cdot \frac{6}{11} = 1\)

б) \(3 - 2\frac{1}{4} = \frac{3}{4}\)

\(3 - \frac{9}{4} = \frac{12-9}{4} = \frac{3}{4}\)

в) \(\frac{5}{9} : \frac{7}{9} = \frac{5}{7}\)

\(\frac{5}{9} \cdot \frac{9}{7} = \frac{5}{7}\)

г) \(\frac{5}{14} - 0,7 = \frac{1}{4}\)

\(\frac{5}{14} - \frac{7}{10} = \frac{50 - 98}{140} = \frac{-48}{140}
e \frac{1}{4}\)

\(\frac{5}{14} : 0,7 = \frac{1}{4}\)

\(\frac{5}{14} \cdot \frac{10}{7} = \frac{50}{98}
e \frac{1}{4}\)

\(\frac{5}{14} + 0,7 = \frac{1}{4}\)

\(\frac{5}{14} + \frac{7}{10} = \frac{50 + 98}{140} = \frac{148}{140}
e \frac{1}{4}\)

\(\frac{5}{14} \cdot 0,7 = \frac{1}{4}\)

\(\frac{5}{14} \cdot \frac{7}{10} = \frac{35}{140} = \frac{1}{4}\)

Ответ: а) \(\cdot\); б) -; в) :; г) \(\cdot\)