Simplify the following text for a Grade 9 native English-speaking person.
Original: Nicolas Gregory Mankiw ( born February 3 , 1958 ) ( known as N. Gregory Mankiw ) is a famous economist who graduated from Princeton University and Massachusetts Institute of Technology .
Simplified: Nicholas Gregory `` Greg '' Mankiw ( ; born February 3 , 1958 ) is an American macroeconomist .