Alright, let's work through 8642 times 9778 step by step
8642 × 9778 = 9778 × (8642)
+ 9778 × 2 which equals 19556
+ 9778 × 40 that is equal 391120
+ 9778 × 600 producing 5866800
+ 9778 × 8000 which equals 78224000

= 84501476
