can do sth on their ear

Bob's your uncle! a bed of roses a piece of cake a walk in the park all downhill as easy as pie be a breeze be a matter of doing something be a piece of cake be an easy touch be as easy as abc be as easy as falling off alog be as easy as pie be as easy as rolling off alog be as easy as taking candy from a baby

الصعوبة والتحدّي الصعوبة والمشقة