381. Сложите дроби: а) 1/4 + 5/6; б) 2/9 + 1/6; в) 1/6 + 3/8; г) 1/12 + 4/15; д) 3/10 + 5/8; е) 7/12 + 1/8; ж) 3/20 + 7/25; з) 2/9 + 7/12.

а) \(\frac{1}{4}+\frac{5}{6}=\frac{3}{12}+\frac{10}{12}=\frac{13}{12}=1\frac{1}{12}\).

б) \(\frac{2}{9}+\frac{1}{6}=\frac{4}{18}+\frac{3}{18}=\frac{7}{18}\).

в) \(\frac{1}{6}+\frac{3}{8}=\frac{4}{24}+\frac{9}{24}=\frac{13}{24}\).

г) \(\frac{1}{12}+\frac{4}{15}=\frac{5}{60}+\frac{16}{60}=\frac{21}{60}=\frac{7}{20}\).

д) \(\frac{3}{10}+\frac{5}{8}=\frac{12}{40}+\frac{25}{40}=\frac{37}{40}\).

е) \(\frac{7}{12}+\frac{1}{8}=\frac{14}{24}+\frac{3}{24}=\frac{17}{24}\).

ж) \(\frac{3}{20}+\frac{7}{25}=\frac{15}{100}+\frac{28}{100}=\frac{43}{100}\).

з) \(\frac{2}{9}+\frac{7}{12}=\frac{8}{36}+\frac{21}{36}=\frac{29}{36}\).