Alright, let's work through 7790 times 2011 step by step
7790 × 2011 = 2011 × (7790)
+ 2011 × 0 that equals 0
+ 2011 × 90 which equals 180990
+ 2011 × 700 resulting in 1407700
+ 2011 × 7000 producing 14077000

= 15665690
