Alright, let's work through 8251 times 8507 step by step
8251 × 8507 = 8507 × (8251)
+ 8507 × 1 what gives us 8507
+ 8507 × 50 that is equal 425350
+ 8507 × 200 yielding 1701400
+ 8507 × 8000 what gives us 68056000

= 70191257
