Question

\(\dfrac{2}{5}\).\(\dfrac{3}{7}\):\(\dfrac{4}{5}\)

\(\dfrac{3}{7}\)-(\(\dfrac{2}{5}\)+\(\dfrac{2}{7}\))

1,25.\(\dfrac{5}{4}\)+2,6

Answer 1

a) \(\dfrac{2}{5}\cdot\dfrac{3}{7}:\dfrac{4}{5}=\dfrac{2}{5}\cdot\dfrac{3}{7}\cdot\dfrac{5}{4}=\dfrac{6}{35}\cdot\dfrac{5}{4}=\dfrac{30}{140}=\dfrac{3}{14}\)

b) \(\dfrac{3}{7}-\left(\dfrac{2}{5}+\dfrac{2}{7}\right)=\dfrac{3}{7}-\dfrac{2}{5}+\dfrac{2}{7}=\left(\dfrac{3}{7}+\dfrac{2}{7}\right)-\dfrac{2}{5}=\dfrac{5}{7}-\dfrac{2}{5}=\dfrac{11}{35}\)

c) \(1,25\cdot\dfrac{5}{4}+2,6=\dfrac{5}{4}\cdot\dfrac{5}{4}+\dfrac{13}{5}=\dfrac{25}{16}+\dfrac{13}{5}=\dfrac{333}{80}\)