Alright, let's work through 4172 times 3990 step by step
4172 × 3990 = 3990 × (4172)
+ 3990 × 2 which equals 7980
+ 3990 × 70 yielding 279300
+ 3990 × 100 producing 399000
+ 3990 × 4000 yielding 15960000

= 16646280
