Question

Вычеслите а) и б) быстрее​

Answer 1

а)  $\left(\dfrac{3}{8} + \dfrac{5}{12}\right)\cdot 4 = \left(\dfrac{9}{24} + \dfrac{10}{24}\right) \cdot 4 = \dfrac{9+10}{24} \cdot 4 = \dfrac{19}{24}\cdot 4 = \dfrac{19\cdot 4}{24} = \dfrac{19}{6} = \boxed{\bf{3\dfrac{1}{6}}}$

б)  $\left(\dfrac{5}{6} - \dfrac{2}{9}\right) : 11 = \left(\dfrac{15}{18} - \dfrac{4}{18}\right) : 11 = \dfrac{15-4}{18} : 11 = \dfrac{11}{18} : 11 = \dfrac{11}{18\cdot 11} = \boxed{\bf{\dfrac{1}{18}}}$