Alright, let's work through 3643 times 221 step by step
3643 × 221 = 221 × (3643)
+ 221 × 3 what gives us 663
+ 221 × 40 what gives us 8840
+ 221 × 600 giving us 132600
+ 221 × 3000 that results in 663000

= 805103
