Alright, let's work through 3866 times 6645 step by step
3866 × 6645 = 6645 × (3866)
+ 6645 × 6 what gives us 39870
+ 6645 × 60 yielding 398700
+ 6645 × 800 what gives us 5316000
+ 6645 × 3000 yielding 19935000

= 25689570
