VTMO 2026 - Grade 9 - Semifinal - SET 2 - Self-study Question 20

Find the units digit of $1\cdot3\cdot5\cdot7+3\cdot5\cdot7\cdot9+5\cdot7\cdot9\cdot11+\cdots+2011\cdot2013\cdot2015\cdot2017$.