fit write sth on the back of a postage stamp

Bob's your uncle! a bed of roses a piece of cake a walk in the park all downhill almost painless amazingly easy any fool can as easy as pie at the push of a button at the stroke of a pen be a breeze be a doddle be a matter of doing something be a piece of cake

الصعوبة والتحدّي الصعوبة والمشقة