Alright, let's work through 3861 times 81 step by step
3861 × 81 = 81 × (3861)
+ 81 × 1 which equals 81
+ 81 × 60 what gives us 4860
+ 81 × 800 that equals 64800
+ 81 × 3000 that results in 243000

= 312741
