Question

4\5 -1\2+3\4=





5\7-1\3+1\2=

Answer 1

$\dfrac{4}{5}- \dfrac{1}{2} + \dfrac{3}{4}= \\ \\ \\ \dfrac{4*4}{5*4}- \dfrac{1*10}{2*10} + \dfrac{3*5}{4*5}= \\ \\ \\ \dfrac{16}{20}- \dfrac{10}{20} + \dfrac{15}{20}= \dfrac{16-10+15}{20}= \boxed{ \frac{21}{20}} \\ \\ \\ \\ \dfrac{5}{7}- \dfrac{1}{3} + \dfrac{1}{2}= \\ \\ \\\dfrac{5*6}{7*6}- \dfrac{1*14}{3*14} + \dfrac{1*21}{2*21}= \\ \\ \\\dfrac{30}{42}- \dfrac{14}{42} + \dfrac{21}{42}= \dfrac{30-14+21}{42}= \boxed{ \dfrac{37}{42} }$