3 >7/8>3/5>4/7

b1:

= \(\dfrac{7}{19} \left(\dfrac{1}{3}+\dfrac{2}{3}\right)\)

= \(\dfrac{7}{19}\times1\)

= \(\dfrac{7}{19}\)

b2 :

x = \(\dfrac{1}{3}\div\dfrac{1}{2}\)

x = \(\dfrac{2}{3}\)

b3 :

x = \(\dfrac{5}{2}\times\dfrac{4}{5}\)

x = 2

b4 :

x = \(\dfrac{2}{9}\div\dfrac{2}{3}\)

x = \(\dfrac{1}{3}\)

ahyhy