Alright, let's work through 3980 times 3911 step by step
3980 × 3911 = 3911 × (3980)
+ 3911 × 0 that is equal 0
+ 3911 × 80 that equals 312880
+ 3911 × 900 resulting in 3519900
+ 3911 × 3000 producing 11733000

= 15565780
