Alright, let's work through 3996 times 4239 step by step
3996 × 4239 = 4239 × (3996)
+ 4239 × 6 what gives us 25434
+ 4239 × 90 what gives us 381510
+ 4239 × 900 resulting in 3815100
+ 4239 × 3000 that results in 12717000

= 16939044
