Alright, let's work through 2638 times 3780 step by step
2638 × 3780 = 3780 × (2638)
+ 3780 × 8 that equals 30240
+ 3780 × 30 resulting in 113400
+ 3780 × 600 that is equal 2268000
+ 3780 × 2000 that equals 7560000

= 9971640
