What is the missing number?

A newly ordained priest, nervous about hearing confessions, finally asks an older priest to observe how he does and give some tips. After listening in on the second confession, the older priest suggested that the younger man fold his arms, maybe rub his chin with one hand while saying phrases like "I see" or "I understand" or "Yes, my child. Go on".
The young priest puts the suggestions into practice and later tells the older priest how much it has helped getting more information from his flock.
"You've done well," said the older man. "Isn't that much better than slapping your knee and yelling 'No way! What happened next?'"