Schoolmaster and professor.

Taught mathematics, writing, and accounting in Philadelphia (from 1734) and Kent County, Maryland (1740-42). Franklin’s son William attended Grew’s school (1738). Consultant on Pennsylvania-Maryland boundary dispute. Professor of mathematics at Academy and College of Philadelphia (1751-59); received honorary A.M. (1757). Published Description and Use of Globes (1753). Contributed astronomical calculations to Poor Richard’s Almanack and Virginia Almanack, among others.

Possibly English; settled in Annapolis by 1732. Married (1) Elizabeth Cosins (1735); (2) Frances Bowen (1739); (3) Rebecca Richards (1747).