Find remainder when dividing upon $2012$ number $$A=1\cdot2+2\cdot3+3\cdot4+...+2009\cdot2010+2010\cdot2011$$
Problem
Source: Regional Olympiad - Federation of Bosnia and Herzegovina 2012
Tags: remainder, number theory
Source: Regional Olympiad - Federation of Bosnia and Herzegovina 2012
Tags: remainder, number theory
Find remainder when dividing upon $2012$ number $$A=1\cdot2+2\cdot3+3\cdot4+...+2009\cdot2010+2010\cdot2011$$