2 Выполните сложение: а) \(\frac{3}{10} + \frac{4}{10}\); б) \(\frac{1}{2} + \frac{1}{2}\); в) \(\frac{3}{7} + \frac{5}{7}\); г) \(\frac{12}{31} + \frac{18}{31}\); д) \(\frac{2}{3} + \frac{3}{3}\); e) \(\frac{4}{5} + \frac{1}{5} + \frac{2}{5}\).

a) \(\frac{3}{10} + \frac{4}{10} = \frac{3+4}{10} = \frac{7}{10}\)

б) \(\frac{1}{2} + \frac{1}{2} = \frac{1+1}{2} = \frac{2}{2} = 1\)

в) \(\frac{3}{7} + \frac{5}{7} = \frac{3+5}{7} = \frac{8}{7}\)

г) \(\frac{12}{31} + \frac{18}{31} = \frac{12+18}{31} = \frac{30}{31}\)

д) \(\frac{2}{3} + \frac{3}{3} = \frac{2+3}{3} = \frac{5}{3}\)

e) \(\frac{4}{5} + \frac{1}{5} + \frac{2}{5} = \frac{4+1+2}{5} = \frac{7}{5}\)

Ответ: а) \(\frac{7}{10}\); б) 1; в) \(\frac{8}{7}\); г) \(\frac{30}{31}\); д) \(\frac{5}{3}\); e) \(\frac{7}{5}\).