10. a) 1/2 + 1/3 + 1/5 10. б) 1/3 + 3/4 + 5/12

Решение:

• a) \( \frac{1}{2} + \frac{1}{3} + \frac{1}{5} = \frac{15}{30} + \frac{10}{30} + \frac{6}{30} = \frac{31}{30} = 1\frac{1}{30} \)
• б) \( \frac{1}{3} + \frac{3}{4} + \frac{5}{12} = \frac{4}{12} + \frac{9}{12} + \frac{5}{12} = \frac{18}{12} = \frac{3}{2} = 1\frac{1}{2} \)

Ответ: а) 1 1/30, б) 1 1/2