Alright, let's work through 8485 times 8638 step by step
8485 × 8638 = 8638 × (8485)
+ 8638 × 5 that is equal 43190
+ 8638 × 80 that is equal 691040
+ 8638 × 400 resulting in 3455200
+ 8638 × 8000 yielding 69104000

= 73293430
