451. Вычислите: а) 3/4 + 2/3; б) 3/5 − 1/3; в) 3/4 − 2/3; г) 3/4 + 3/14.

а) \(\frac{3}{4}+\frac{2}{3}=\frac{9}{12}+\frac{8}{12}=\frac{17}{12}=1\frac{5}{12}\).

б) \(\frac{3}{5}-\frac{1}{3}=\frac{9}{15}-\frac{5}{15}=\frac{4}{15}\).

в) \(\frac{3}{4}-\frac{2}{3}=\frac{9}{12}-\frac{8}{12}=\frac{1}{12}\).

г) \(\frac{3}{4}+\frac{3}{14}=\frac{21}{28}+\frac{6}{28}=\frac{27}{28}\).

Ответ: а) \(1\frac{5}{12}\); б) \(\frac{4}{15}\); в) \(\frac{1}{12}\); г) \(\frac{27}{28}\).