Alright, let's work through 5039 times 4029 step by step
5039 × 4029 = 4029 × (5039)
+ 4029 × 9 resulting in 36261
+ 4029 × 30 that equals 120870
+ 4029 × 000 which equals 0
+ 4029 × 5000 that results in 20145000

= 20302131
