Ta có: $\\$ `4/6=(4xx2)/(6xx2)=8/12`$\\$ `8/12=(8xx6)/(12xx6)=48/72=(48:4)/(72:4)=12/18`$\\$ `12/18=12/18`$\\$ `12/18=(12xx2)/(18xx2)=24/36`$\\$ `24/36=(24xx4)/(36xx4)=96/108=(96:3)/(144:3)=32/48`$\\$ `32/48=(32xx7)/(48xx7)=224/336=(224:8)/(336:8)=28/42`$\\$ Vậy các ô cần điền như sau: $\dfrac{4}{6}=\dfrac{8}{\boxed{12}}=\dfrac{\boxed{12}}{18}=\dfrac{12}{\boxed{18}}=\dfrac{\boxed{24}}{36}=\dfrac{32}{\boxed{48}}=\dfrac{\boxed{28}}{42}$