Alright, let's work through 8547 times 840 step by step
8547 × 840 = 840 × (8547)
+ 840 × 7 that equals 5880
+ 840 × 40 yielding 33600
+ 840 × 500 which equals 420000
+ 840 × 8000 that results in 6720000

= 7179480
