Alright, let's work through 3993 times 8138 step by step
3993 × 8138 = 8138 × (3993)
+ 8138 × 3 producing 24414
+ 8138 × 90 giving us 732420
+ 8138 × 900 that equals 7324200
+ 8138 × 3000 yielding 24414000

= 32495034
