Gọi phân số cần tìm là x
--> $\dfrac{7}{9}$ < x < $\dfrac{8}{9}$
Ta có: $\dfrac{7}{9}$ = $\dfrac{35}{45}$
$\dfrac{8}{9}$ = $\dfrac{40}{45}$
--> $\dfrac{35}{45}$ < x < $\dfrac{40}{45}$
--> x = $\dfrac{36}{45}$ ; $\dfrac{37}{45}$ ; $\dfrac{38}{45}$ ; $\dfrac{39}{45}$
--> x = $\dfrac{4}{5}$ ; $\dfrac{37}{45}$ ; $\dfrac{38}{45}$ ; $\dfrac{13}{15}$
Vậy 4 phân số cần tìm là: $\dfrac{4}{5}$ ; $\dfrac{37}{45}$ ; $\dfrac{38}{45}$ ; $\dfrac{13}{15}$