Meeting the parents and children for the first time

I am interviewing for a job in a few days where I will be meeting the parents and the children I will be tending to. My question is, how am I suppose to act around them. I want to seem responsible to the parents, but still be fun at the same time for the children. Do I ask the children questions, like what they like to do? I know the parents want to see how I interact with their children, but I don't want to seem rude, like I am ignoring the parents. I know that along the way, I need to ask any questions I have, but if the parent wants to observe the way the children and I interact, do I act as though the parent isn't there? Any help that parents nd/or babysitters can give me would be great. Thanks in advance...
K