Question

Answer 1

\(a,\dfrac{3}{4}+\dfrac{2}{5}+\dfrac{3}{12}=\left(\dfrac{3}{4}+\dfrac{3}{12}\right)+\dfrac{2}{5}=\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\dfrac{2}{5}=1+\dfrac{2}{5}=\dfrac{5}{5}+\dfrac{2}{5}=\dfrac{7}{5}\\ b,\dfrac{47}{15}+\dfrac{40}{17}-\dfrac{4}{30}-\dfrac{6}{17}=\left(\dfrac{47}{15}-\dfrac{4}{30}\right)+\left(\dfrac{40}{17}-\dfrac{6}{17}\right)=\left(\dfrac{47}{15}-\dfrac{2}{15}\right)+2=3+2=5\)