Verb conjugation of "invocar" in Spanish

My wife an I have decided that as long as our children were small and would not have to go to school we need to take advantage of our freedom and travel as much as possible. Later this year we will go to Costa Rica.
A ten year old kid should not be on Facebook. I would not be too concerned about your boys, because with facebook they can see who is approaching them, that means they can see the profile and social structure of their friends.
First, let me thank you for your answer. And how can I support you further? I'd be very happy about it if we could both help in each other in learning Spanish. 'Tandem' learning beats all other methods.