Краткое пояснение: В первом задании нужно разделить \(\frac{1}{7}\) на каждое из чисел, а во втором – прибавить \(\frac{1}{12}\) к каждому из чисел.
a)
- \(\frac{1}{7} : \frac{2}{7} = \frac{1}{7} \cdot \frac{7}{2} = \frac{1}{2}\)
- \(\frac{1}{7} : \frac{1}{7} = 1\)
- \(\frac{1}{7} : 2 = \frac{1}{14}\)
- \(\frac{1}{7} : \frac{5}{7} = \frac{1}{7} \cdot \frac{7}{5} = \frac{1}{5}\)
- \(\frac{1}{7} : \frac{1}{9} = \frac{1}{7} \cdot 9 = \frac{9}{7}\)
- \(\frac{1}{7} : \frac{6}{21} = \frac{1}{7} : \frac{2}{7} = \frac{1}{7} \cdot \frac{7}{2} = \frac{1}{2}\)
- \(\frac{1}{7} : 1 = \frac{1}{7}\)
- \(\frac{1}{7} : \frac{12}{7} = \frac{1}{7} \cdot \frac{7}{12} = \frac{1}{12}\)
- \(\frac{1}{7} : 2 = \frac{1}{14}\)
б)
- \(\frac{1}{12} + \frac{1}{4} = \frac{1}{12} + \frac{3}{12} = \frac{4}{12} = \frac{1}{3}\)
- \(\frac{1}{12} + (-\frac{1}{3}) = \frac{1}{12} - \frac{4}{12} = -\frac{3}{12} = -\frac{1}{4}\)
- \(\frac{1}{12} + (-1) = \frac{1}{12} - \frac{12}{12} = -\frac{11}{12}\)
- \(\frac{1}{12} + \frac{5}{12} = \frac{6}{12} = \frac{1}{2}\)
- \(\frac{1}{12} + \frac{1}{12} = \frac{2}{12} = \frac{1}{6}\)
- \(\frac{1}{12} + (-\frac{7}{12}) = \frac{1}{12} - \frac{7}{12} = -\frac{6}{12} = -\frac{1}{2}\)
- \(\frac{1}{12} + (-\frac{1}{6}) = \frac{1}{12} - \frac{2}{12} = -\frac{1}{12}\)
- \(\frac{1}{12} + \frac{1}{6} = \frac{1}{12} + \frac{2}{12} = \frac{3}{12} = \frac{1}{4}\)
- \(\frac{1}{12} + (-\frac{1}{4}) = \frac{1}{12} - \frac{3}{12} = -\frac{2}{12} = -\frac{1}{6}\)