Alright, let's work through 6440 times 888 step by step
6440 × 888 = 888 × (6440)
+ 888 × 0 that results in 0
+ 888 × 40 what gives us 35520
+ 888 × 400 yielding 355200
+ 888 × 6000 that equals 5328000

= 5718720
