Alright, let's work through 8402 times 2457 step by step
8402 × 2457 = 2457 × (8402)
+ 2457 × 2 what gives us 4914
+ 2457 × 00 that is equal 0
+ 2457 × 400 giving us 982800
+ 2457 × 8000 what gives us 19656000

= 20643714
