Alright, let's work through 8009 times 6391 step by step
8009 × 6391 = 6391 × (8009)
+ 6391 × 9 resulting in 57519
+ 6391 × 00 that equals 0
+ 6391 × 000 which equals 0
+ 6391 × 8000 what gives us 51128000

= 51185519
