An Elizabeth High School math teacher was arrested last week and charged with having sexual contact with a 14-year-old over four months starting in October, authorities said Monday. Bipradas Mookerjee, 72, of North Brunswick, was charged with third-degree aggravated criminal sexual contact and third-degree endangering the welfare of a child, according to Union County Prosecutor William A. Daniel and city police Chief Giacomo Sacca. Elizabeth police received a report several weeks ago involving the 14-year-old girl. The complaint was forwarded to the prosecutor’s special victim’s unit, Daniel a…