Alright, let's work through 3969 times 6400 step by step
3969 × 6400 = 6400 × (3969)
+ 6400 × 9 resulting in 57600
+ 6400 × 60 yielding 384000
+ 6400 × 900 what gives us 5760000
+ 6400 × 3000 which equals 19200000

= 25401600
