1) a) \(\frac{3}{16} + \frac{5}{8}\) г) \(\frac{19}{21} - \frac{3}{7}\) 6) \(\frac{5}{6} - \frac{2}{3}\) д) \(\frac{1}{2} + \frac{1}{5}\) в) \(\frac{4}{15} + \frac{13}{45}\) e) \(\frac{1}{4} - \frac{1}{5}\)

Решение

1) a) \(\frac{3}{16} + \frac{5}{8} = \frac{3}{16} + \frac{5 \cdot 2}{8 \cdot 2} = \frac{3}{16} + \frac{10}{16} = \frac{3 + 10}{16} = \frac{13}{16}\) г) \(\frac{19}{21} - \frac{3}{7} = \frac{19}{21} - \frac{3 \cdot 3}{7 \cdot 3} = \frac{19}{21} - \frac{9}{21} = \frac{19 - 9}{21} = \frac{10}{21}\) 6) \(\frac{5}{6} - \frac{2}{3} = \frac{5}{6} - \frac{2 \cdot 2}{3 \cdot 2} = \frac{5}{6} - \frac{4}{6} = \frac{5 - 4}{6} = \frac{1}{6}\) д) \(\frac{1}{2} + \frac{1}{5} = \frac{1 \cdot 5}{2 \cdot 5} + \frac{1 \cdot 2}{5 \cdot 2} = \frac{5}{10} + \frac{2}{10} = \frac{5 + 2}{10} = \frac{7}{10}\) в) \(\frac{4}{15} + \frac{13}{45} = \frac{4 \cdot 3}{15 \cdot 3} + \frac{13}{45} = \frac{12}{45} + \frac{13}{45} = \frac{12 + 13}{45} = \frac{25}{45} = \frac{5 \cdot 5}{5 \cdot 9} = \frac{5}{9}\) e) \(\frac{1}{4} - \frac{1}{5} = \frac{1 \cdot 5}{4 \cdot 5} - \frac{1 \cdot 4}{5 \cdot 4} = \frac{5}{20} - \frac{4}{20} = \frac{5 - 4}{20} = \frac{1}{20}\)