Alright, let's work through 8420 times 7663 step by step
8420 × 7663 = 7663 × (8420)
+ 7663 × 0 what gives us 0
+ 7663 × 20 giving us 153260
+ 7663 × 400 which equals 3065200
+ 7663 × 8000 that is equal 61304000

= 64522460
