Resources to Support Challenging Child Behavior

Sitting at Supper
Situation: 

My child is 5 years old and cannot sit through dinner with the family. He will jump up, come back take a few bites, if any bites at all, bang on the table, and sometimes just leave and play with his toys. We never have a peaceful family meal. Any suggestions?

Work Ahead Flexibility: Math
Situation: 

I have a bright student in my math class. She knows much of the work and when we start the workbook pages she wants to keep working ahead. If I make her wait or stop her from continuing the back side she will tantrum. What can I do to make her follow along with the class?

Behavior Story: Restaurant
Situation: 

My child has a very difficult time going to family-style restaurants. In particular, he has difficulty sitting and waiting quietly, eating neatly, and interacting with the waiter or waitress. How can I help my child learn to be more appropriate in this setting?