Alright, let's work through 6400 times 2051 step by step
6400 × 2051 = 2051 × (6400)
+ 2051 × 0 what gives us 0
+ 2051 × 00 that equals 0
+ 2051 × 400 producing 820400
+ 2051 × 6000 that equals 12306000

= 13126400
