ГДЗ Математика 6 клас Істер — Вправа 285

1) $4\frac{7}{10} + 2\frac{4}{5} = 4\frac{7}{10} + 2\frac{8}{10} = 6\frac{15}{10} = 7\frac{5}{10} = 7\frac{1}{2};$

2) $5\frac{3}{5} + 7\frac{5}{6} = 5\frac{18}{30} + 7\frac{25}{30} = 12\frac{43}{30} = 13\frac{13}{30};$

3) $7\frac{9}{14} + 1\frac{16}{21} = 7\frac{27}{42} + 1\frac{32}{42} = 8\frac{59}{42} = 9\frac{17}{42};$

4) $5\frac{7}{8} + 9\frac{11}{20} = 5\frac{35}{40} + 9\frac{22}{40} = 14\frac{57}{40} = 15\frac{17}{40}.$