Simplify the following text for a Grade 11 native English-speaking person.
Original: They have three children : Constanze ( 1971 ) , Veronica ( 1977 ) , Dominic ( 1980 ) and four grandchildren : Johannes ( 1999 ) , Benedikt ( 2001 ) , Theresa Marie ( 2005 ) and Ferdinand ( 2009 ) .
Simplified: They have three children : Konstanze ( 1971 ) , Veronika ( 1977 ) , Dominik ( 1980 ) and three grandchildren : Johannes ( 1999 ) , Benedikt ( 2001 ) and Theresa Marie ( 2005 ) .