Alright, let's work through 4540 times 3643 step by step
4540 × 3643 = 3643 × (4540)
+ 3643 × 0 which equals 0
+ 3643 × 40 which equals 145720
+ 3643 × 500 that results in 1821500
+ 3643 × 4000 that results in 14572000

= 16539220
