Alright, let's work through 8120 times 5251 step by step
8120 × 5251 = 5251 × (8120)
+ 5251 × 0 producing 0
+ 5251 × 20 producing 105020
+ 5251 × 100 what gives us 525100
+ 5251 × 8000 producing 42008000

= 42638120
