№1. Выполните действия: a) 6+3 5+2 б) 2 1 5 + 2 7 в) 8 + 10 г) 8 3.10. 11 10.6 д) - 5 е) 25:; 18.12.4 35 ж) 7:28;

а) \(6 + \frac{5}{3} = \frac{6 \cdot 3}{3} + \frac{5}{3} = \frac{18}{3} + \frac{5}{3} = \frac{18 + 5}{3} = \frac{23}{3} = 7\frac{2}{3}\)

б) \(2 \frac{1}{5} + \frac{2}{5} = \frac{2 \cdot 5 + 1}{5} + \frac{2}{5} = \frac{10 + 1}{5} + \frac{2}{5} = \frac{11}{5} + \frac{2}{5} = \frac{11 + 2}{5} = \frac{13}{5} = 2\frac{3}{5}\)

в) \(8 + \frac{7}{10} = \frac{8 \cdot 10}{10} + \frac{7}{10} = \frac{80}{10} + \frac{7}{10} = \frac{80 + 7}{10} = \frac{87}{10} = 8\frac{7}{10}\)

г) \(8 \frac{3}{11} = \frac{8 \cdot 11 + 3}{11} = \frac{88 + 3}{11} = \frac{91}{11} = 8\frac{3}{11}\)

д) \(10 \frac{6}{5} = \frac{10 \cdot 5 + 6}{5} = \frac{50 + 6}{5} = \frac{56}{5} = 11\frac{1}{5}\)

е) \(\frac{18}{25} : \frac{12}{35} = \frac{18}{25} \cdot \frac{35}{12} = \frac{18 \cdot 35}{25 \cdot 12} = \frac{630}{300} = \frac{63}{30} = \frac{21}{10} = 2\frac{1}{10}\)

ж) \(\frac{4}{7} : 28 = \frac{4}{7} : \frac{28}{1} = \frac{4}{7} \cdot \frac{1}{28} = \frac{4 \cdot 1}{7 \cdot 28} = \frac{4}{196} = \frac{1}{49}\)