Alright, let's work through 8215 times 857 step by step
8215 × 857 = 857 × (8215)
+ 857 × 5 that is equal 4285
+ 857 × 10 which equals 8570
+ 857 × 200 giving us 171400
+ 857 × 8000 what gives us 6856000

= 7040255
