Alright, let's work through 3581 times 814 step by step
3581 × 814 = 814 × (3581)
+ 814 × 1 yielding 814
+ 814 × 80 giving us 65120
+ 814 × 500 giving us 407000
+ 814 × 3000 giving us 2442000

= 2914934
