((2/7)+3(1/2)×4(2/3)=17(2/3)
1) (2/7)+(7/2)=(2×2+7×7)/14=(4+49)/14=(53/14)
2) (53/14)×(14/3)=(53×14)/(14×3)=(53/3)=17(2/3)
(4(1/5)-2(3/4))×2(2/19)=3(1/19)
1) (21/5)-(11/4)=(21×4-11×5)/20=(84-55)/20=29/20
2) (29/20)×(40/19)=(29×20×2)/(20×19)=(58/19)=3(1/19)