Alright, let's work through 4002 times 4003 step by step
4002 × 4003 = 4003 × (4002)
+ 4003 × 2 that is equal 8006
+ 4003 × 00 which equals 0
+ 4003 × 000 that is equal 0
+ 4003 × 4000 yielding 16012000

= 16020006
