Alright, let's work through 4084 times 9405 step by step
4084 × 9405 = 9405 × (4084)
+ 9405 × 4 giving us 37620
+ 9405 × 80 resulting in 752400
+ 9405 × 000 yielding 0
+ 9405 × 4000 producing 37620000

= 38410020
