Alright, let's work through 4711 times 8420 step by step
4711 × 8420 = 8420 × (4711)
+ 8420 × 1 what gives us 8420
+ 8420 × 10 what gives us 84200
+ 8420 × 700 yielding 5894000
+ 8420 × 4000 which equals 33680000

= 39666620
