An elder couple

An elder couple was lying in bed after they awakened just chatting. The husband suggested whomever thought of the best rhyme could get breakfast in bed. She thought a bit and said: "Ok, shoot."

He thought for a bit and then said: “2 and 2 are 4, 4 and 5 makes 9, I've got my hand on yours, you've got your hand on mine.” She thought a bit then said: "2 plus 2 is 4, 4 and 5 makes 9, I know the length of yours, you don't know the depth of mine."