Master numbers? Oh yeah! Ira mentally slapped herself when it dawned on her. They had studied it last term, hadn't they?

She raised her hand up and answered, "11, 22 and 33 are master numbers...." But why were they called so? Ira thought about it. She just knew one thing and so she said it, "I just know that the Master numbers can't be reduced to single digits. They are somehow special."

Saying so, Ira sat down and waited for the professor to explain further.