Alright, let's work through 4038 times 4640 step by step
4038 × 4640 = 4640 × (4038)
+ 4640 × 8 that results in 37120
+ 4640 × 30 what gives us 139200
+ 4640 × 000 that equals 0
+ 4640 × 4000 that results in 18560000

= 18736320
