Alright, let's work through 3906 times 665 step by step
3906 × 665 = 665 × (3906)
+ 665 × 6 that results in 3990
+ 665 × 00 that equals 0
+ 665 × 900 that equals 598500
+ 665 × 3000 which equals 1995000

= 2597490
