3. Выполните сложение дробей. Запишите ответ в виде дроби (при необходимости сократите): 1) 2 1/3 + 1 2/5; 2) 3/7 + 2 4/7; 3) 1 5/6 + 2 1/4; 4) 4 2/15 + 1 7/15; 5) 5 3/8 + 1 1/2; 6) 7/9 + 3 2/9; 7) 6 1/10 + 2 3/5; 8) 1 11/14 + 2 3/7; 9) 3 5/12 + 2 1/6; 10) 4 7/18 + 1 5/9; 11) 2 1/4 + 3 5/5; 12) 5 1/6 + 2 7/12.

1) Приводим дроби к общему знаменателю: \(2\frac{1}{3}+1\frac{2}{5}=3+\frac{5}{15}+\frac{6}{15}=3\frac{11}{15}\).

2) \(\frac{3}{7}+2\frac{4}{7}=2+\frac{7}{7}=3\).

3) \(1\frac{5}{6}+2\frac{1}{4}=3+\frac{10}{12}+\frac{3}{12}=4\frac{1}{12}\).

4) \(4\frac{2}{15}+1\frac{7}{15}=5\frac{9}{15}=5\frac{3}{5}\).

5) \(5\frac{3}{8}+1\frac{1}{2}=6+\frac{3}{8}+\frac{4}{8}=6\frac{7}{8}\).

6) \(\frac{7}{9}+3\frac{2}{9}=3+\frac{9}{9}=4\).

7) \(6\frac{1}{10}+2\frac{3}{5}=8+\frac{1}{10}+\frac{6}{10}=8\frac{7}{10}\).

8) \(1\frac{11}{14}+2\frac{3}{7}=3+\frac{11}{14}+\frac{6}{14}=4\frac{1}{14}\).

9) \(3\frac{5}{12}+2\frac{1}{6}=5+\frac{5}{12}+\frac{2}{12}=5\frac{7}{12}\).

10) \(4\frac{7}{18}+1\frac{5}{9}=5+\frac{7}{18}+\frac{10}{18}=5\frac{17}{18}\).

11) \(2\frac{1}{4}+3\frac{5}{5}=5+\frac{1}{4}+1=6\frac{1}{4}\).

12) \(5\frac{1}{6}+2\frac{7}{12}=7+\frac{2}{12}+\frac{7}{12}=7\frac{3}{4}\).